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A MODERN MANCFACTORY OF CANNING MACHINERY. 



Science and 

Experiment as Applied 

to Canning 



EDITED BY 

O. L. DEMING 

OF THE "CANNER AND 
DRIED FRUIT PACKER" 



v^^-^" 




PUBLISHED BY 

SPRAGUE CANNING MACHINERY CO., 
CHICAGO 



THE LIBRARY OF 
CONGRESS. 

Onf Copy Receivbc) ; 

NOV. ^ 190? 



A\ 



r^ 



COPYRIGHTED, 1902, 

BY 

O. X,. DEMING, 

CHICAGO. 



INDEX 



PACiE 
I I - 



Introdiidion 

Historical "^ ' "■♦ 

First l)i^cussioll on Sour Corn, by Mr. W. Lyman Underwood ==; - ^^ 

First Discussion on Sour Corn, by i'rof. S. C. I'rescott 3^ - 

Souring of Corn '*-• " ^- 

Detoction ol' Spoiled Cans ■»"> * 

Bacteriology of Sour Corn '^4 'Ti^^ 47 - 49 

Process of i'acking Corn 37 - 

Method of Sterilization 4=^ - 

Whiteness of Canned Corn 4^ - 

Maxinuini Temperature within Cans 4t> - 

Descriptions of Bacteria =^7 - ^6 

General Discussion 4^ - ■■ -^ 

Calcium Process "^^ 

Illustrations of Modern Corn Machinery '^ - 44 

Cause and Prevention of Sour Corn, by i'rof. S. C. Prescott t)7 - 74 

Cause and Prevention of Sour Corn, by Mr. W. Lyman Underwood 7=i - ^4 

Joint Letter, bv Prof. S. C. Prescott and Mr. W. Lyman Undeiwood 85 - 87 

Bacteria in Canned Food, by Mr. Wm. Lyman Underwood 8q - 07 

Souring of Peas "^ - ^7 

The Use of Preservatives, by Prof. S. C. Prescott qo - lo. 

Sanitary Conditions, by Mr. W. Lyman Underwood 'o=^ - "^^ 

Control of Insect Injury to Corn, by Prof. Forbes " " - '"» 

Pea Pests, by ProL J. C Sanderson ' = 1 - ' ^tj. 1 47 - 101 

The Green Pea Louse, by Prof. W. G. Johnson '-7 - '4" 

Process of Packing Peas, by C. H. Plummer '"'^ - '^^ 

llUistration'< of .Modern Pea Machinery '"^ - '7= 



INTRODUCTION. 



The editor of the Canner and Dried Fruit Packer has frequently re- 
ceived requests for copies of issues containing the various valuable scientific 
articles which have appeared from time to time in its columns, and as it 
is no longer possible to furnish a complete set of such articles in that form 
it has been suggested that the more important articles be combined, and 
published in book form. Acting on this suggestion, which I consider 
timely and even vital to the interests of the canning trade, I have gathered 
together such articles as are essential to a work of this character and offer 
them with the hope that they will materially assist in placing the canning 
business on a more accurate and therefore more scientific basis. 

The principal papers are from the pens of Prof. S. C. Prescott, of the 
Massachusetts School of Technology, and W. Lyman Underwood, of Bos- 
ton, Mass., who are the pioneers in bacterial research as relating to canned 
goods and to whom the canners of the United States owe a debt of gratitude 
if nothing more. A sort of strange coincidence is connected with the first 
investigation into the causes which developed sour corn and which had 
proved a serious menace to the packers of that article. Mr. W. Lyman 
L'nderwood is a member of the firm of Wm. L^nderwood & Co., of Boston, 
which firm, with other articles of food, is a heavy packer of lobsters, which 
from an early date gave much trouble and anxiety to the packer by 
frequently turning black in the can. After various reasonings 
and experiments, all of which resulted unsatisfactorily, Mr. Un- 
derwood decided to make a thorough scientific study of the ques- 
tion, and, under the advice and leadership of Professor S. C. Prescott, 
entered into an exhaustive research and investigation of the bacteria af- 
fecting lobster. As Mr. Underwood pursued his studies he became enthused 
with the \v(n-l<, and, idgciluT with Professor Prescott. continued his 
investigations in other lines of canned goods, chiefly corn, and later on 
peas. Eastern canners first became aware of the scientific work being done 
bv these gentlemen and naturally became very much interested and even 
anxious to learn the results of these pioneer investigations into the almost 
unknown ground of liacteria as relating to canned goods. It is a remark- 
able fact that up to the time of these investigations by Professors Prescott 
and Underwood the "art" of canning was a dense and tangled underbrush 

1 1 



of theories, hedged about by mysterious nods and winks ; factories were 
jealously guarded as if they contained some enchanted secret and it was 
almost as difficult to secure admission as it was to break into the vaults of 
a bank. All this arose from carefully guarded ignorajice on the part of 
the canner and his desire to protect what little information he possessed re- 
garding the process of canning. The canner himself really knew so little 
about the science of canning that he was compelled through caution to 
throw the glamour of secrecy over nearly every movement in order to pro- 
tect himself and his lack of skillful knowledge. Canning seemed more 
like an intrigue than a legitimate commercial business ; the act of self- 
interest which brought Mr. Underwood and Professor Prescott together 
was really the first attempt ever made to place the canning business on a 
safe and solid basis of action. 

The growth of the industry has been very rapid, and the development 
of the machinery for the different operations necessary in canning fac- 
tories has kept pace with its enlargement. The opening article, 
containing an outline of the early history of the corn packing in- 
dustry, will be of interest to all, with its illustrations of the crude appliances 
first used. Devices first starting with home made and experimental ap- 
paratus were developed in a scattered way throughout the pioneer facto- 
ries in the industry. Necessity has never more truly proved its title, 
" the mother of invention " than in the canning line. From the crude ex- 
perimental machines there have been developed for the purposes of the can- 
ner, machinery and appliances, perfect in all their details, and automatic 
in their operations, many of which have a capacity for handling products 
in different departments at a rate of upwards of 40,000 cans in ten 
hours ; automatic canning lines have been developed in which each machine 
has been designed with particular view to its automatic operation and re- 
lation to other machines performing the different parts of the work, and 
instead of canning machinery being made in a small way by scattering in- 
dividuals and inventors throughout the country, there are now manufac- 
turing concerns of considerable size devoting their attention exclusively 
to the manufacture of canning machinery and appliances, and the further 
perfecting of automatic systems for handling every article put into a can. 

Papers by the well-known entomologists Professor E. Dwight Sander- 
son, of Newark. Del., and Professor W. G. Johnson, of Maryland, as well 
as other authorities, are also incorporated in the compilation. 

THE EDITOR. 



12 



CHAPTER 



HISTORICAL. 

The most reliable historical article on the caiinins^ of corn ever pvil)lished 
is from the pen of Mr. F. O. Conant. of Portland, Ale. The article was 
written by request and the author made most careful and thorough search 
of many historical documents for the facts presented. The article w^as read 
at the annual canners' meeting held at Cincinnati in February, 1897. Mr. 
Conant addressed the convention as follows: 

Gentlemen : W' hen our president asked me to prepare a paper for this 
meeting I could think of no subject connected with the packing industry 
with which I was familiar enough to prepare a paper which would be 
likely to have any interest to a body composed principally of Western pack- 
ers, except a sort of sketch of the early days of the trade in Maine. It 
may seem like presumption for one whose connection with trade has been 
so short to attempt this subject, but the sources of information are open 
to all. and many of the pioneers are still with us in Maine, able and willing 
to give information to those who seek it, and so I decided to make the at- 
tempt though very conscious of my own deficiencies and lack of ability. 

The evolution of the canning business is a very interesting phase of 
the life of the down-Fast wage earner, and many who were once wage earn- 
ers are now capitalists, owing the bulk of their fortunes to the canning busi- 
ness. It is well-known that the jirocess of preserving food in bottles by 
a method quite similar to our present process of canning is not a recent in- 
vention. The first record of it appears in a paper submitted by the English 
Society of Arts in 1807. under the title "A Method of Preserving Fruits 
Without Sugar for House or Sea Stores." bv a Mr. Saddington. The 
method then described was to fill bottles with fruit, loosely cork, place them 
in a vessel containing cold water, which should reach to the necks of the 
bottles, and gradually raise the heat to a temperature of about 75 degrees, 
keeping it there for half an hour. The manipulator was cautioned not to 
heat higher or longi r or the bottles would lie liable to burst. Then the 
bottles were to be filled with boiling water, corked immediately and laid 
upon their sides in order that the hot water might swell the corks. The 
operation was completed by cementing the corks. Credit has generally been 
given, however, to M. Appcrt. a Frenchman, who was the first to make i)rac- 

13 



tical use of the process on a large scale. His work on the subject was pub- 
lished in 1810, he having received a prize of 12,000 francs offered by the 
French government in 1809. There was also an English patent granted in 
1810 to Peter Durrand for preserving animal food, vegetable food and 
other perishable articles. 

The method of preserving food by canning in its present form appears 
to date back to the patent of Pierre Antoine Angilbert in 1823, though it 
is said to have been in practical use three years earlier. This method did 
not vary essentially from present practice. The food, together with some 
water was placed in a tin can, a lid carrying a minute aperture fastened on and 
heat applied. When the liquid in the can boiled briskly, and all the air had 
been expelled, the hole was closed by a drop of solder. 

Maine has been generally acknowledged as the early home of corn pack- 
ing in this country, and its claim is a just one. Some small quantities of 
oysters were packed in Baltimore, and lobsters, fish and perhaps fruits were 
packed elsewhere previous to the canning of corn in Maine, Edward Wright 
having started to pack oysters in Baltimore between 1838 and 1840. The 
late Thomas Kensett, who was considered one of the fathers of the in- 
dustry, did not establish his business in Baltimore till 1850. At about the 
same time as Wright, Isaac Winslow began his experiments in canning corn 
at or near Portland. Isaac Winslow was a native of Maine and at some 
time previous to 1840 was engaged in the whaling business with a brother 
who lived in France. During some of his visits to France he learned of 
the process of preserving foods, probably through the purchase of supplies 
to fit out his whaling ships, and conceived the idea of preserving green 
vegetables by hermetically sealing them in cans. Scurvy, a disease brought 
on by sameness of food, was then a dreaded disease among sailors, so a per- 
son connected with the sea would be quick to see the advantage of such 
a process, which would enable vessels to carry a varied diet safely pre- 
served against the varying temperature a long voyage would necessitate. 
Winslow too had a fondness for inventions and inventors and at this 
time had nearly dissipated a large fortune in advances to inventors of 
numerous processes, machines, and articles, all of which were warranted 
by the inventor to make the owner and controller of the invention im- 
mensely wealthy within a short time. Some of us machinery men have 
had similar sad experience, so when you packers object to the profits of 
certain machines, please remember the good money which has gone into 
unfruitful experiments and the long series of trials necessary before the 
first inventive idea results in the perfect machine. 

Isaac Winslow, then, in 1839 began his experiments on corn, which for 
a long time proved unsuccessful. He, about 1842, arranged with Caleb 
Jones, a brother-in-law, (and father of John Winslow Jones, at one time 
the king of the caiTned goods trade in Alaine), to plant a piece of green 
corn for experimental purposes. This is the first appearance of the name 
of Jones in connection with the industry. Winslow's first trial was by 
cooking the whole ear of corn, but the article obtained was so bulky and 
he thought the cob absorbed the sweetness, that this way was abandoned 



14 



also, and he next tried to remove the kernels whole by pulling or pushing 
them off the ear with a kind of fork. But this was soon abandoned also, 
and the kernels cut from the cob. The first experiments in cooking were 
made in a common household boiler and in a very small way. When boil- 
ing he was accustomed to treat little lots to varying degrees of heat and 
various times, then mark each lot and pile it away and await results. The 
results were mostly one way, that is, the corn spoiled after a little while, 
but enough kept to give Mr. Winslow confidence in his ultimate success, 
and this confidence was increased from the fact that the portion of corn 
which kept proved to be of very superior quality and was much compli- 
mented by his friends, among whom he distributed it. In 1843 ^^^ prepared 
for more experiments and caused to be built a small steam boiler made 
of copper that would hold about two barrels of water and would carry 10 
or 12 lbs. of steam, and attached to tiiis wooden tanks lined with zinc 
and made steam tight. In these tanks he processed his corn, subjecting it 
to the direct action of steam without water. For some reason nearly the 
whole lot experimented upon in that year spoiled, and the steam apparatus 
was abandoned. The next season, or in 1844, he went back to the process 
of boiling in open boilers. About 1842 Nathan Winslow, a brother of 
Isaac, joined with him in the experiments. Nathan Winslow was a dealer 
in stoves and tinware, and his shop was next to my grandfather's place of 
business on Fore street, Portland. The cans used in these experiments 
were made in his shop and I have heard my father relate that about this 
time the rumor that the Winslows were engaged in some secret experiment 
being noised about, he with other boys climbed the roof of his father's store 
and so gained access to a scuttle window in the roof of the Winslow store 
where he could see Winslow and his workmen busily engaged in making 
tin cans of a strange form. They were of strange form, as the example I 
now exhibit will show. This is supposed to contain corn, though that is 
not certain. At any rate it is one of the cans packed by Nathan Winslow 
about 1852. 

Isaac Winslow continued his experiments with varying success until 
about 1853, when, thinking the process had at last reached a stage warranting 
the step, he applied for a patent. His claim for the protection of a patent 
was not allowed at this time, and it was not till 1862 that the patent was 
finally issued, and then it was to John Winslow Jones, assignee of all in- 
terests to Isaac Winslow. An extended abstract from the original patent 
(or patents, for there were four of them) of Winslow may be of interest. 
He says, " After a great variety of experiments I have overcome the diffi- 
culties of preserving Indian corn in the green state without drying the same, 
thus retaming the milk and other juices, and the full flavor of fresh, green 
corn, until the latter is desired for use. Instead of a hard, insipid or other- 
wise unpalatable article, I have finally succeeded in producing an entirely 
satisfactory article of manufacture, in which my invention consists. I 
have employed several methods of treatment — my first success was ob- 
tained by the following process : The kernels being removed from the cob 
were immediately packed in cans and the latter hermeticallv sealed, so as 

15 




CAN USED BY CORN PACKERS ABOUT 1852 



16 



to pcrvent the escape of the natural aroma of tlie corn, or the evaporation 
of the miUv and other juices of the same; then 1 submitted the sealed cans 
and their contents to boiling or steam heat about four hours. In this way 
the milk and other juices of the corn are coagulated as far as may be, 
boiling thus preventing the putrefaction of these most easily destructible 
constituents. At the same time the milk is not washed away or diluted, as 
would be, more or less, the case if the kernels were mixed with water and 
then boiled. By this method of cooking green corn the ends of the cans 
are bulged out as though putrefaction and escape of the resultant gases had 
commenced within the cans ; conse(|uently strong cans are required, and 
dealers are likely to be prejudiced against corn thus put up. I recommend 
the following method : Select a superior quality of green corn in the green 
state, and remove the kernels from the cob by means of a curved and gauged 
knife or other suitable means. Then pack these kernels in cans and her- 
metically seal the latter so as to prevent evaporation, under heat, or the 
escape of the aroma of the corn. Now expose these cans of corn to steam 
or boiling heat for about one hour and a half ; then puncture the cans, and 
immedialely seal the same, while hot ; and continue the heat for about two 
hours and a half longer. Afterwards the cans may be slowly cooled in a 
room at a temperature of 70 degrees to 100 degrees Fahrenheit." For 
many years the fact of the preservation of foods treated by these processes 
was ascribed solely to the fact that all air is expelled from the can during 
the process of canning, it being supposed that air was absolutely essential 
to the growth of putrefaction germs. But this is not so, for it is well 
known to scientists that some of the common bacteria which cause putre- 
faction can live without atmospheric air or that air is even fatal to them. It 
follows that the mere presence or absence of air in the can is a matter of 
no importance in itself. Tyndall demonstrated that air plays no important 
part in putrefaction save as a carrier of bacteria. Winslow was well aware 
that it was not the air inside the can which spoiled the corn, for he says : 
" The air contained within the cans at the time of sealing and also the vapor 
from the corn become more or less expanded, so as to press out the heads 
of the can, thus giving the appearance of s]wiled corn. WMicn the cans 
are not punctured their ends will remain outward after cooling, and yet 
the corn is perfectly preserved." 

Xathan \\'inslow engaged in jjacking as a business in 1852, and in 
1853 took his nephew, John Winslow Jones, into company with him. Their 
business graduallv increased and the firm continued in the trade till 1861 
or 1862, after which time Jones continued the Inisiness alone, and for many 
years was the largest packer in the state, and in addition to the corn packed 
by himself, bought largely of others, selling all under the well known 
yellow label bearing the title "Winslow's Patent Hermetically Sealed 
Green Corn." The first sale of corn which has been found is from Nathan 
Winslow to Samuel S. Pierce of Boston, the invoice being dated Feb. 19, 
1848, and was for one dozen canisters preserved corn at $4.00. 

In 1867 Jones brought suit against R. K. Sewall, administrator of the 
estate of Henry Clark of Wiscassett. Maine, for packing corn without a 



17 



license. This suit was bitterly fought in the U. S. Circuit Court before 
Judge Clifford and a decision was not given till iVlay, 1873, when an ac- 
counting was ordered ahd an injunction given. In course of this suit nearly 
every person who had ever been connected with the canning business in 
Maine gave testimony on one side or the other. This decision favorable 
to the Winslow patents caused great commotion among the packers all over 
the country, and some hastened to take licenses from Jones, then 
owner of the patents. They agreed to pay a royalty of 25 cents per 
dozen on all corn packed for the remainder of the life of the patent or till 
1878. An appeal was, however, taken to the Supreme Court of the United 
States and in October, 1875, Judge Clifford's decision was reversed and 
the Winslow patents declared invalid. 

In June, 1876, Jones having secured a patent on an improved knife for 
cutting the corn from the cob and also by surrendering his former patents 
and amending specifications having secured a new patent on the process, 
brought suit against Louis McMurray & Co., of Baltimore. This suit, 
like the earlier one, drew into it as witnesses or interested parties nearly 
all who had ever had anything to do with canning all over the country. 
This suit was finally compromised. 

Mr. Jones, in 1880, organized the John Winslow Packing Co., Ltd., 
in which a large amoimt of English capital was interested, but for some 
reason the company was unsuccessful, and was succeeded in 1882 by the 
Winslow Packing Co., organized by Col. C. P. Mattocks of Port- 
land, which did a very large business for several years packing corn and 
lobsters principally, and in 1887 sold 203,000 cases of corn which was sold 
at $1.10 to $1.25 per dozen. Their brands were the Globe (170,000) and 
Snow Flake (63,000). 

Mr. Jones afterwards removed to Maryland and is still selling corn 
packed at Portland, but the letters indicating the state upon his labels are 
Md. instead of Me. 

When the Winslow Packing Co. went out of business, a large number 
of firms for whom it had acted as selling agents began packing on their 
own account and under their own brands, and new companies were or- 
ganized to operate its abandoned factories. Among these were A. & P. B. 
Young of Hiram, the Minot Packing Co., of West Minot, the Norway 
Packing Co. and others 

In 1839 Upman S. Treat of Eastport, Maine, engaged in packing sal- 
mon at St. Johns, N. B., and in 1841 removed to Eastport, where the firm 
of Treat, Noble & Co. was formed, composed of Treat, Isaac Noble, 
Charles Mitchell, Tristram Halliday, and engaged in packing lobsters and 
salmon. Treat withdrew from the firm in 1843 ^nd the business was 
carried on by Noble and Mitchell. Treat afterward entered the business 
again. They put up some corn for experiment at an early period and 
continued in business till 1856. The corn canned by them was shipped from 
Boston by steamer. Treat claimed that he sold the first canned salmon that 
was ever sold in this country in 1841, and that he put canned lobsters on 
the market in 1842 or 1843. He claimed that at that time he visited all 

18 



the large cities, Boston, New York, i'liiladelphia, Baltimore and Washing- 
ton, withont findini^ canned salmon or lobster. 

Noble & Mitchell sold out to William Underwood & Co. about 1843, 
who did not pack corn largely themselves, but bought from others. The 
firm of W. K. Lewis & Bros, seems to have been the next firm to engage 
in the trade. They put up some goods in Boston in 1843, ^'■'t i" 1845 started 
a factory in Portland on Custom House Wharf, preserving mostly meats, 
fish and perhaps some corn. 

In 1849 Henry Evans, afterward of the firm of Evans, Reeves & Co. of 
New York and llaltimore, had a packing shop on Custom House Wharf 
near Lewis' shop. He learned the trade of I'. S. Treat at Eastport. He 
only remained in Portland about a }ear. 

In the same year Aarijn Ring opened a cannery in Portland, packing 
lobsters, peas, meats, etc.. on Burnham's Wharf. He soon took into part- 
nership with him a man named 1 lartshorn. Ring was afterward processor 
for Henry Clark, the man against whom Jones brought suit. In 1853 Ring 
put up about 20,000 cans and in 1S54 about 40,000 cans. 

The next firm to enter the business was Rumery & Burnham. com- 
posed of Samuel Rumery, who died some twenty-three years ago, and 
George Burnham, jr.. now the senior nuniljir of the Burnham & Morrill Co. 
Samuel Rumery had learned the trade at Eastport with Treat, Noble & 
Co. about 1844 or 1845, l^c was next a member of the firm of Lewis & 
Co., at Portland, in 1846 and 1847. ^^^en was with Nathan Winslow & Co. 
in 1849. I" 1850 he was with Wells. Miller & Provost in New York City, 
but soon returned to l^ortland and in 1852 went into business with George 
Burnham. who had learned the trade with Lewis & Co. Their principal 
business was at first the packing of meats, fish, clams, poultry, and lobsters, 
but corn was added to the list about 1853 or 1854. In 1855, they bought 
out Kemp, Day & Co., who had started a packing house near the entrance 
to the canal. Kemp. Day & Co.'s shop was built over a large depression 
in the ground, but not a regular cellar, and after Rumery & P)urnham 
moved into it they found this hollow under the building full of cans of 
spoilt corn, which had been hidden there by the workmen without the 
knowledge of Kem]i, Day & Co. It was estimated that there were 10.000 
cans in the lot, and as corn then sold at $3.50 per dozen, this would account 
for (|uite a portion of the loss they admitted by this wniuri.'. Rumery 
& Burnham continued in business together till i8()7. when the partnership 
was dissolved and the firm of Burnham & Morrill formed, which continued 
till within a few years, when the business was incoriioratcd as the Burn- 
ham «!<: .Morrill Co. 

The firm of Davis, Baxter & Co. was the next firm to enter the business. 
The\ had been engaged in importing cutlery and fancy goods for some 
years. Init in 1861 began to pack lobsters, and 1862. in connection with 
Rumery & Burnham. established the Portland Packing Co. The company 
was owned jointly for about four years, when Davis, Baxter & Co. bought 
the interests of Rumery & Burnham. When the firm of Rumery & Burn- 
ham dissolved in 1867 or 1868, Rumery joined the Portland Packing Co.. 

19 



whicli was then composed of William (i. Davis, James P. Baxter, now 
and for three years past Mayor of I'ortland, and Samuel Rnmery, who 
continued in the firm till his death in ICS74. The firnris still in existence, 
doing a large business, and now composed of sons of the original pro- 
prietors. 

Plummer & Marr were one of the early firms in the business. They had 
a factory in Portland and another at South Paris, but sold out to the 
Portland Packing Co. about 1866. 

A. H. Burnham, of Bridgton, who is well known to many of you, having 
attended these conventions for many years, began business with Xathan 
Winslow in 1852. He was then with Rumery & Burnham for a while, but 
soon went back with Winslow and continued with him and his successor, 
Jones, as long as they remained in business. For a runnber of years he 
was general superintendent of the Winslow Packing Co.'s factories in the 
western part of the state, had a better practical knowledge of the business 
than he. He now runs his own Waterford factory, and is also interested 
in the two factories of the Bridgton Canning Co. 

J. P. Jordan first entered the business as broker in 1879, but in 1882 
began packing on his own account at New (Gloucester, and in 1884 added 
other factories, organizing "The United Packers," of which he is treasurer, 
in 1889. His office in Portland is in the same building occupied back in 
the "forties" by Nathan Winslow, Maine's first corn packer. 

H. F. WeblD & Co. began business in 1881 at Rumford, but of late years 
have packed the largest part of their output at Leeds and Gray. His 
"Cream" brand has a high reputation with the trade. Mr. Horace F. 
Webb, of this firm, is a son of Mr. James B. Webb, who first entered the 
packing business at Gorham, Me., about i8r>5, as a member of the old Gor- 
ham Packing Co. 

In 1888, a number of new firms entered the field, among them H. -C. 
Baxter & Bro., Fernald & Keene Bros., now Fernald, Keene & True Co., 
the Winterport Packing Co. 

There are many other firms as deserving of record as those mentioned, 
but time forbids. Among those still in active business are Fred T. Flint, 
with factories at Cornish and Kczar Falls; T. L. Eastman, Fryeburg; 
Merrill Bros., with factories at Lisbon and Yarmouth ; E. S. Coding, at 
Livermore Falls; Bonney, Wheeler & Dingley Co., Farmington Falls; N. 
C. Cumings & Bro., Portland; Henry S. Payson Co., Portland; Henry L. 
Forhan, Ravmond ; C. T. Moses, Corinna ; Norton & Wingate, Flast Bald- 
win ; Twitchell, Chamjilin & Co., and Thompson & Hall, of Portland ; J. & 
E. H. Wyman, Readfield, and D. W. Hoegg & Co. 

Like most other manufacturing industries carried on by enterprising 
and ingenious men, the method and process of packing sweet corn has 
undergone a complete change since its commencement, though the princi- 
ple remains the same. This is mostly through the use of improved ma- 
chinery. At first the corn was cut from the cob by a common case knife ; 
the knife then took a curved form, shaped to the ear of corn, and a gauge 
added before 1853. Tn these days the cutters were the most numerous body 

20 



cou.v ■"( I rii;u" of IsV) 




TIIK riliST SI'UAlJfK fOltX CI'TTKH (I NVK.NTK ).\ DF W I'. I .CO M K SIMIAOKK 



21 



of workmen about the factory. For instance, in the year 1869, 800 hands 
were employed at the Bridgton factory, of whom 375 were cutters and 
only about 100 buskers. This continued until about 1875, when machines 
run b}' hand came out, invented by Volney Barker. The power machines 
came into use about 1886. Sprague's first and then the Barker machines. 

Jones was the first packer to use ice for the purpose of keeping the corn 
cool from the time of cutting till filled into cans. This he did about 1863. 

The old hand press for filling cans came into use at an early period in 
the history of the industry and was not superseded, in Maine, at least, by 
machine work until quite recently. In 1878 Barker took out his first pat- 
ents on a power filler, but not until 1885 was his machine made practical, 
and then it was totally unlike the first one. The Stickney filler came out 
in 1883 and had a large sale. These machines were in general use when the 
hot process which had been used in the south for a number of years was 
introduced in 1890. Wiping machines were introduced by Barker about 
1883, but the brush machines have displaced his machine since 1888. 

In the "sealing" department Maine is perhaps behind other states, for 
most factories still "cap" by hand. Some power capping machines have, 
however, been introduced, and we may expect their use to become general 
very quickly. Mr. E. M. Lang of Portland has introduced several valua- 
ble improvements in soldering irons, one of which was introduction of a 
tool made of steel instead of copper. Mr. Lang's patent was granted in 
1876, but he never enforced his claims to royalty, and the patent expired in 
1893. Mr. Lang was also the inventor and patentee of segment solder, 
which he introduced in 1876. 

The processing of the corn also shows the march of improvement. At 
first many packers outside of the Winslows cooked the corn before filling 
it into the cans. The Winslows filled the cans with uncooked corn, then, 
after sealing, the cans were cooked in an open bath for about two hours, 
vented, resealed, and boiled for two hours and a half or three hours longer. 
Some packers vented twice with a cooking of an hour and a half between, 
and a total time of about five and a half hours. The time of the "bathing" 
was gradually reduced, in one case by the addition of salt or chemicals to 
the water, which then required a higher temperature to boil it, and so per- 
mitting a shorter cooking. About 1879 the time was still farther shortened 
by the introduction of steam retorts, which reduced the time of the last cook- 
ing to one hour. Next and last came in the "cookers" (Conant's, of course, 
preferred), which did away with the first bath, and also with a large num- 
ber of hands previously needed in the bath room. 

It is probably safe to say that Maine has packed more corn than 
any other state, and for the last five years Maine's pack has been second only 
to that of New York, Maine having produced 3,101,883 cases and New 
York 4,378,000. Illinois comes third with a pack of 2,352,000 cases. 

This paper has been confined closely to the canning industry as related 
to com, but Maine firms are heavy packers of lobsters, sardines, blue- 
berries, clams, etc., but I am not familiar enough with the subject to attempt 
it in this paper. 

22 




TIIK SI'H MifECOUN Crn-KI! OF ]'.HC U.ATKST f Ml- UOV i:l) MODKI, M) 



23 



In conclusion, let me say that I have endeavored to outline the evolution 
of the canning industry in Maine. Speaking of the discovery of the art 
in general, it was a revolution, for l)y its realizations ayd its future possi- 
hilities this discovery was of the greatest economic value in preventing 
the waste of property, giving of employment to millions of capital and thou- 
sands of laborers. It gives employment to the miner in the mountains of 
Wales and in the coal and iron fields of our own countrw to the lumber- 
man and nail manufacturer, to the farmer, the laborer, the machinist, the 
engraver, the printer, the artist, and gives thousands of car loads of freight 
to the railroads. It would be difficult to find an industry in which greater 
variety of talent and skill is employed or one in which the investor finds 
so large and profitable a field. Its products are truly cosmopolitan, for 
they go north, south, east and west, and are available in every climate. 
Maine is a small state, compared with its sisters in the west and south, 
and the area in which sweet corn can be grown and packed is limited, but 
as an ofifset to our long, cold winters, our rocks and hills, we can boast 
that Maine produces the best sweet corn in the world. 

(Mr. Conant at the next annual meeting held at Lkift'alo. February. 
i8e)8, referred to his paper of the previous year. His remarks were some- 
what supplementary to this paper, as they embodied the discoveries of a 
recent research which he had made among the papers belonging to the His- 
torical Society of Maine. In the paper of the preceding vear it was brought 
out that the first instances in canning known were of the date 1807 or 
i8io. In the second research he had found a paper of the date of January 
(J, 1840, which contained an item stating that twelve tin packages contain- 
ing k'rench peas were fotmd in the wreck of the Royal George, which oc- 
curred August 29, 1792, or nearly twenty years previous to the earliest 
known history regarding the packing of canned goods. Mr. Conant re- 
ferred to the fact that it was about the time of the date of the publication 
of this paper in 1840 that Xathan Winslow first commenced experimenting 
in the processes of canning vegetables, and thought the inference very strong 
that Nathan Winslow received his first inspirations from the paragraph re- 
fcrre<l to. This is certainly a very valuable acquisition to the canning his- 
tory of America.) 



24 



CHAPTER II. 

Tlic letter wliicli follows answers as an introduction to ilic jjapers and 
discussion on tlie souring of corn. This letter was written in Xoveniber. 
1897. l)y W. Lyman I'nderwood, and the comment which follows ajipcarcd 
in the L.\.\.\i:k and Drikd Fkiit Packkr of Xovemher 4, 1897: 

DETERIORATIOX IX CAXXHL) (iOODS. 

Editor Cainicr ami Pried fruit I'arkcr: 

As yoii doubtless know much interest has been manifest in some quarters regard- 
ing the deterioration occurring in some kinds of canned goods, of which lobsters and 
corn arc two notable examples. In Canada the question has become so serious, that 
the Canadian government recently employed a specialist to investigate the lobster 
packing business, with the view to finding out the causes of deterioration of canned 
lob-ter (i .e.. black lobster), and if possible to find methods of prevention. This, 
however, is not the first work which has been done on this subject. On Octol)er 8. 
1896. a paper on "micro-organisms and sterilizing processes in the canning indu>iries" 
was read before the Society of Arts in Boston by Mr. C. S. Prescott. of the Massa- 
chusetts Institute of Teclinology. and myself, and afterwards published in tiie I cell - 
iiuloiiy Quarterly. Vou may also l)e interested to learn that for nearU' a year we have 
been investigating the bacteria conceived in the spoiling of corn, "sour corn," and hope 
to publish an article on this subject in a short time. 

W. 1AM \.\ rXDF.KWt'Ol). 

'I'he ])a])cr referred to in the above letter will prove interesting to the 
packers of canned ^oods. We regret limited s])ace will not ])ermit the ])tibli- 
cation in this issue. The authors have carefully reviewed the canned ij^oods 
industry in the L'nited States, and have devoted considerable study to 
processes in canning;. I'nder the head of Examination of "Swelled" Cans 
and l)escri])tions of the liacteria hound, they sav : ( )ur investisjations 
beij^an with a careful examination of a larye number of cans of s])t)iled clams 
and lobsters. The contents of such cans were found to be badly decoiu- 
posed. in some cases ahuost entirelv li(|uefied, much darkened in color, 
and of a verv (lisa!.j;reeable odor. I'acterial exatuination showed that in 
every case where sjjoilinj;- had occurred, living" bacteria were present in 
great numbers. In sound cans, on the other hand, no living bacteria could 
be detected, and the conteiUs proved to be sterile. As would be supjxised 
in the present state of bacteriology, there is no reason to doubt that swelling 

25 



and decomposition are invariably the result of bacterial action. In some 
cases a can contained a culture apparently pure, while other cans might 
contain a mixture of sweet species. The ordinary bacteriological methods, 
with some modifications, served for the separation of these organisms into 
distinct species, and made possible their cultivation in pure cultures in arti- 
ficial media. Of the nine species of bacteria obtained, two are micrococci, 
while the other seven are classed among the bacilli. All of them are no- 
ticeably rapid in their development in an incubator at blood heat (98 deg. F., 
374 C.) both in liquid and on solid media, while they grow slowly at a tem- 
perature of 70 deg. F. (20 deg. C). They may be readily stained by the 
usual staining reagents. In some several of the forms endospore forma- 
tion has been observed, and these forms are likewise noticeable for the 
rapidity with wdiich sporulation occurs. Detailed descriptions are given 
which show some of the characteristics of the above species. 



FIRST PAPERS ON SOUR CORN. 



At the annual meeting of the Atlantic States Packers' Association held 
at Buffalo in February, 1898, President Palmer announced that the commit- 
tee had secured the presence of Prof. Prescott and also W. Lyman PTnder- 
wood, who would discuss in detail the results of their investigations. These 
gentlemen addressed the convention Wednesday, February 9th, and were 
introduced by the chair, as follows : 

Several years ago Mr. Underwood, of the firm of Underwood 
& Co., of Boston, began the study of bacteriology at the Massachusetts 
School of Technology, and has been following it ever since, with the 
special object of solving some of the problems which have arisen in the 
canning business. Mr. William Underwood is a member of the firm of 
Underwood & Co., and he and his family have been in the canning business 
for three generations. His grandfather was one of the pioneers. As you 
know they are packers of high grade fish, meats, soups, etc., and have a repu- 
tation throughout the country. Mr. Prescott is a professor at the institute, 
and Mr. Underwood and Mr. Prescott together have been studying this 
subject, and they wish it to be understood and given out that their labors have 
not been separated in any way. What they have found out, and what they 
have done has been the result of their joint work. I think these papers are 
going to be of a great deal of use to the canned goods packer. It is a subject 
that is very important indeed, and "sour corn" has caused the packers of 
corn to lose thousands of dollars in the last few years. The paper which is 
to be read by Professor Prescott is going to be published in the Technology 
Quarterly, which will appear about March i, and therefore he wishes it 
given out that it will not be printed in full by the trade papers until it so 
appears, as his work was done in the interest of the institution, and the 
Quarterly publishes this kind of work, and they feel they are under obliga- 

26 



tions to have it appear iti the Quarterly first. Mr. Undcrwoud will speak 
to you first. 

Mr. Lnclcrvvood spoke as follows: 

It gives both .\lr. I'rcscott and myself great pleasure to address you this 
morning, and it is our hope that some benefit may come from the work which 
we have undertaken. We shall not attempt to lay down any hard and fast 
rules for the prevention of some of these troubles, which occasionally make 
themselves manifest in the canning industry. It is probable that, at times, 
we have all of us had more or less spoiling of some of our products. 

It may interest you to hear how I happened to take up this studv of germs 
or bacteria, in coiuieclion with my Inisiness. Some three or four vears ago 
I became aware i)f an eiuirely new form of spoiling, in some of the goods 
which we packed. This was similar in a way to that which sometimes takes 
place in canned lubster. kn^wn to ilie trade as "Black Lobster." The con- 
tents of the can were turned to a black, foul smelling liquid, witlnmt swelling 
or giving any outward indications of anything being wrong within. Lnck- 
ily this condiliiin of things was discovered at the factory before anv ship- 
ments were made: for by shaking the cans their liquid nature would be de- 
tected. At the same time we were having a good manv swells in the same 
goods. 

I was a great deal wdrried and naturalK \er\- anxious to find the cause 
of this new state of things. 1 had an idea, as. of course, most of you have, that 
to kill all germs was one of the fundamental ]:)rinciples of canning ; though 
just what these germs were, was very dim in my mind, neither did I, at the 
time, in any way, connect them with our trouble. It seemed to me more a mat- 
ter of chemistry. But after a great deal of chought I finally went to the 
Massachusetts Institute of Technology, and consulted with Prof. W. F. 
Sedgwick and explained to him the nature of the difficulty. He told me 
that, to his knowledge, no scientific investigations had been made of the 
canning industry, and it seemed to him that bacteria or germs were the cause 
of the trouble, and to become acquainted with these things would require the 
study of 1 bacteriology. Accordingly, I became associated with Mr. S. C. 
Prcscott of the Biological Department of the Institute. He taught me the 
princi])les of Bacteriology -.vhich apply to our business: while, at the same 
time, lie learned from me that practical part of canning which ap])lies to his 
study. 

It was some time before wc began actual work on spoiled goods, our 
progress at first being naturally slow. This work being entirely new. many 
experiments had to be made and methods devised to obtain satisfactorv 
results. Then, too. my time was limited and our work had to be done after 
business hours. With the aid of microscopes, wc fonnd cans of spoiled goods 
fairly alive with microbes or germs. 

Difficulty now came in making them grow outside the cans: so that the 
different species might be separated and the peculiarities of each be watched 
and studied. Manv attempts were made to make them grow on different 
substances and in different kinds of liquid foods. The temperature favor- 



able to their growth had also to be determined. Our failures were so numer- 
ous that I should have been many times tempted to drop the whole matter 
as impracticable, had it not been for Mr. Prescott's persistency and perse- 
verance. However, we finally succeeded in making them grow in a modified 
form of nutrient agar and were enabled to separate out and obtain pure cul- 
tures of several different varieties. You may be interested to see in a wav 
how this is done. 

(Mr. Underwood here demonstrated the actual method of procedure 
used in obtaining pure cultures of bacteria. ) 

About a year after we began this work, we were enabled to find the cause 
and apply the remedy, some account of which we published last spring in 
the Technology Quarterly. This investigation being now well in hand, we 
were eager to extend our knowledge and accordingly began to work on "sour 
corn." 

Before listening to our paper on this subject I would like to explain in 
a simple way about these germs, microbes or bacteria. 

(ierms, microbes and bacteria are used in a popular sense somewhat indis- 
criminately, all meaning the same thing. They are sometimes more broadly 
classed micro-organisms, but this term includes all small living things, such 
as yeasts and moulds. The general public associates the word bacteria with 
disease and sickness and it is very hard to dispel the idea. As a matter of 
fact, the percentage of disease germs to those that are harmless and those 
which do actual good, is very small indeed. I might liken them to our trees 
and plants. Very few of them are poisonous, many are harmless, and a ma- 
jorit}' are of use and benefit. 

So far as we can find out, these germs, which we have found, are in no 
way disease-producing, anv more than are those which cause milk to sour. 
If a person likes sour milk he will contract no disease from drinking it. 
Many bacteria are in the air which we are breathing at this moment. They 
are in the water which we drink, and in the food which we eat. The best 
of milk contains them in large numl)ers. In a teaspoon ful of good sweet 
milk there are many thousands. So you see that bacteria, as a rule, are not 
to be dreaded. These germs are so very small that it is hard to convey to 
you an accurate idea of their minuteness; 1-20,000 of an inch does not mean 
much to }'ou, yet it would be a fair sized bacillus. If our e\es were one 
thousand times as powerful as they are, we should just be able to see them. 
In form thev vary somewhat. Those that we have foiuid in spoiled goods 
are of two different types — micrococci and bacilli. The cocci are round like 
minute balls. There are different ways in wdiich thev grow. Some grow 
singly; some in pairs; some in long chains like a necklace; some in regular 
bunches of four, six or eight, and some grow in clusters like bunches of 
grapes. The dift'erent kinds often vary in size. The l)acilli arc rod-shaped 
and they also vary in size. Some are very short — so short that it is diffi- 
cult to distinguish them from the cocci or balls. Some are very long, in pro- 
portion like a lead pencil, and the}- occur in diff'erent wa\s, very often in 
chains like strings of sausages. 

28 



In ^(.'iKral lliL'ir i^rowlh is very sinipk' ami is by division, each i^vrni 
dividin!^ and forminf^ two. IikKt favorable conditions their fjrowth is very 
ra])id. Some of the rod-shaped varieties, for instance, divide every twenty 
minutes, and at ihis rale al llie end of ten hours one will have multiplied to 
over 4.000.000,000. 

'!"() illustrate a practical evidence of this rajjid ,i;rowth, two cans of corn 
were inoculated with some of these .qerms and placed in an incubator at a 
temjierature of 89 i-"ahrenheit about 4 o'clock one afternoon. ( )n reaching 
the factorv the next morning about 8 we were much astonished and dismayed 
to find the top of the incul)ator blown off, and the ceiling decorated with ker- 
nels of corn. l)Oth cans had burst during the night, their tops being lorn 
completelv oft. This jiressure was caused by the ferineiUaiion and formation 
of gas b\- the ra])id growth of ihe baclerii. 

Manv of ihe rod^shaped forms of bacilli have a peculiarity which en- 
ables ihem lo resisl heal lo a great extent. These forms are called spores 
and thev are the curse of the canning industry. When they are in this 
stage a i)oiling temperature has ap]iarently no effect Ujjon them, unless long 
continued, how long is not (lefinitel\ known. We have found some that have 
stood a boiling temperature for eight hours and have thrived with this treat- 
ment. When seen under the highest power of the microi'cope many varie- 
ties of the rods or bacilli, in their ordinary active state, resemble small sau- 
sages darting and twisting in all directions. In the spore state, however, 
thev resemble small oval beads and have no motion. 

When in their normal condition microbes are easily killed at a boiliiig 
heat, and many will succumb even at a lower temperature. Most of the disease 
germs luckily'are killed at 212 degrees or lower. It is hard to accurately de- 
termine the temperature necessary to sterilize or kill these s])ores as some are 
much more resistant than others. So far as our experience goes, 250 Fahr- 
enheit has been sufficient, but it must be certain thai whatever heat is re- 
(|uire(l. it shall have reached the center of each can. We have found germs 
in spoiled goods, and that they are the cause of this deterioration we have 
])roved. bv inoculation ; or ])lacing these same germs into good cans, through 
a small liole which was immediately closed. We have thus j^roduced the 
same characteristic spoiling ihal we originally found. To further prove 
that this spoiling was cause<l bv germs alone, and not by air. we have admit- 
ted ])tu-e air. free from germs, into good cans, sealed and placed ihem in 
an incubator (at a constant temptrature of ()3 j-'ahrenlieii ) and for many 
months they have remained sound. iliMugJi some "i ihem were not o])ened 
until a year afterwards. 

( Mr. I'nderwood here showed the method of inoculating cans and also 
showed cans which had been inoculated and had turned sour, and also cans 
into which air free from germs had been admitted and which were perfectly 
sweet, although they had been ke])t for eighl months.) 

There is room for a gr.at deal of scientific work in our business; as each 
class of canned food probably h.as its germs which prey upon it. and each is 
affected by heat in different wavs. Some work of this kind has been under- 
taken by one or two of our colleges, but with no tangible results. 

29 



As yet bacteriology has been but little studied from a commercial stand- 
point ; but I think the time is not far distant when processing by the "rule of 
thumb," will be a thing of the past in the packing- business, in Boston the 
Massachusetts Institute of Technology has taken up this work and is pre- 
pared to teach the scientific principles underlying the process of canning. 
They are now provided with retorts and all necessary apparatus under the 
supervision of Mr. Prescott, and I should recommend anyone having unac- 
countable trouble with their product, to consult with him, as the Massa- 
chusetts Institute of Technology is the only place that I am aware of that 
can carry on these investigations in a practical as well as scientific manner. 

Throughout his discourse Mr. Underwood exhibited to the members of 
the convention photographs of the different forms of bacteria found in corn 
which have been reproduced and may be found directly following the ad- 
dress of Prof. Prescott. Mr. Underwood's paper was received with much 
applause and appreciation. 

At the conclusion of Mr. Underwood's address Prof. S. C. Prescott was 
introduced by President Palmer. 

PROFESSOR PRESCOTT'S PAPER. 

In a paper read before the Society of Arts in October, 1896, we showed 
the extent of the canning industr}- in this country and the importance 
to it of accurate knowledge of the bacteriological principles of steriliza- 
tion. In that paper we dealt with the packing of clams and lobsters, 
and described some of the bacteria which are active in the deterioration 
of these products in case sterilization is not complete. It is interesting 
tO' notice that some of the results which we published at that time have 
since been confirmed by a specialist employed by the Canadian Govern- 
ment to investigate the discoloration of canned lobsters. 

We now desire to give an account of our more recent investigations in 
another branch of the industry, namely, the packing of sweet corn. This 
art constitutes a very large industry, as is shown by the fact that in 1895 
seventy-two million 2-pound cans (72,000 tons) were packed in the United 
States. 

HISTORICAL. 

The growth of the art has been rapid, for it was not until about 1853 
that corn was packed at all with success. Maine has been generally acknowl- 
edged as the home of corn packing, and its claim to be so considered 
is probably just. In 1839 Isaac Winslow began experiments in canning 
corn at or near Portland. He was for a long time unsuccessful. He first 
attempted to cook the ears of corn whole, but this proved unsatisfactory 
on account of their bulk, and it Avas also thought that the cobs absorbed 
the sweetness. He next tried to remove the kernels whole by means of 
a fork, but this was soon abandoned, and the corn was afterward cut 
from the cob. His first experiments were made in a common household 

30 



wash boiler, and in a very limited way. Small quantities were treated 
by various methods, but nearly all the corn spoiled. Some kept, how- 
ever, and gave promise of ultimate success. In 1843 ^'^^ built a small copper 
steam boiler of about two barrels capacity, and carrying- ten or twelve 
pounds of steam. To this he connected wooden tanks lined with zinc and 
made steam tight. In these crude retorts he "processed" the corn, subject- 
ing it to the direct action of li\e sleani. Nearly the whole lot spoiled, 
and in consequence of this failure sleam apparatus was abandoned. The 
next year he returned to open boilers, and continued his experiments with 
varying success for ten years. Tn 1853 lie ai)plic(l for a patent, but this 
was not allowed until 1862. 

An abstract of the patent may be of interest: After a great variety of 
experiments I have overcome the tlifficulties of preserving Indian corn 
in the green state without drying the same, thus retaining the milk and 
other juices, and the full Havor of the fresh green corn until the latter is 
desired for use. Instead of a hard. insi])i(l. or otherwise unpalatable arti- 
cle, I have finally succeeded in producing an entirely satisfactory article of 
manufacture, in which my invention consists. I have employed several 
methods of treatment. ^ly first success was obtained l\v the following 
process: The kernels being removctl from the cob were immediately 
packed in cans, and the latter hermetically sealed so as to prevent escape of 
the natural aroma of the corn, or the eva])oration of the milk or other juices 
of the same. I'lieii 1 submitted the sealed cans and their contents to boiling or 
steam heat for aljoul four hours. In this way the milk and other juices 
of the corn are coagulated as far as nia\ be, boiling thus preventing the 
putrefaction of these most easily destructil)le constituents. At the saine 
time the milk is not washed away or diluted, as would be more or less the 
case if the kernels were mixed with water and then boiled. By this method 
of cooking green corn the ends of the cans are bulged out, as through putre- 
faction and the escape of the resultant gases had commenced within the 
cans. Consequently strong cans are required. 

"I recommend the following method: Select a superior quality of the 
green corn in the green state, and remove the kernels from the cob by 
means of a curved or gauged knife or other suitable means. Then ])ack 
these kernels in cans and hermetically seal the latter so as to prevent the 
evaporation under heat or the escape of the aroma of the corn. Now ex- 
pose these cans of corn to steam or boiling heat for about one hour and a 
half, and then puncture the cans and immediately seal the same while hot, 
and continue to heat for about two and one-half hours longer. Afterwards 



*Mr. Prescott is Instructor in Biology, IMassachusctts Institute of Tech- 
nology, and Mr. Underwood is of the \\'illiam Underwoo<l Co.. Boston. 

'*=* Technology Quarterly, \''ol. X. No. i, Mareli, 1897, P'i,?cs 183-199. 

***Canadian Department of Marine and Fisheries. 29th .\nnual Report. 
Supplement No. 2. Ottawa. 1897. 

31 



the can may he slo\vl\- cooled in a room at a temperature of 70 cleg, to 100 
deg. F." 

For nearly twenty years this method was in use, the only change being 
that the time of processing was shortened. About 1897 retorts were intro- 
duced in corn packing, and the second heating was done in them, the time 
being reduced from two and one-half hours to one. The advent of cookers 
about 1890 did away with the first heating in the water bath, so that now this 
is abandoned as an agency of sterilization. ]\Iany of the processes formerly 
carried on by hand are now carried on by machinery. Aiaine leads in the 
packing of sweet corn, but large quantities are packed in New York and 
Maryland and in the west, particularly in Iowa, Illinois and Michigan. 



THE SOURING OF CANNED SWEET CORN. 

Sweet corn, when properly prepared, is one of the most valuable of all 
canned goods, as it retains much of its original flavor, is popular, and is sold 
at a price wathin the reach of all. If, however, the sterilizing has not been 
done thoroughly, there may result fermentation caused bv bacteria which 
have not been killed, producing what is known as "sour corn. It is not 
definitely known when sour corn first appeared. In the experiments of Isaac 
Winslow, spoiling of some kind resulted, but so far as we have been able 
to ascertain, its nature has never been described. In a Massachusetts fac- 
tory, however, where corn has been packed with success for nearly twenty 
years, souring suddenly occurred in 1878. Maine was also somewhat af- 
fected at the same period. Until this time corn had been processed for five 
hours at a boiling temperature with no loss, Init in the year just mentioned, 
with exactly the same treatment, this manufacturer experienced a total loss. 
Some of this corn was sent to chemists for analysis with the hope that a rem- 
edy might be found at once. It was reported by them to be due to "fungus 
consisting of little-globules that boiling heat did not dissolve."" 

Early in the following year (1879) the Massachusetts packer who 
owned the factory referred to attempted to continue with the old process but 
the corn spoiled. Retorts were procured and with their higher heat 
satisfactor\- results were obtained. For sixteen successive years he 
experimented with the old process with the intention of returning to it if 
possible. The corn so packed and kept at a temperature of 90 to 100 deg. 
F., invariably spoiled, swelling on the third or fourth day. It was thought 
that the trouble might be local, and to decide this he visited dififerent sec- 
tions, carefully selected and gathered corn, and, returning at once to the 
factory, packed it in the old way with the least possible delay, working some- 
times all night that this might be done. The results were always the same 
— the corn could not be successfully packed by the old method. Had any 
locality been found where this could have been done, he intended to remove 
his factory to that neighborhood. 

The exact chemical changes which take place when sour corn is ])roduced 
are difiicult to state, and yar\- under different condititjus. The sugar and 

32 



starch in the corn are fermented for the most part U) lactic, acetic, and liuty- 
ric acid, thus jrivinj;' rise to tlie sourinj;-. Tiiere are also other products of 
decomposition, (iases are frequently evolved, hut heinj? dissolved by the 
li(|uid in the can at the ordinary tem])erature. in the majority of cases no 
swelling- results. 

The loss resulting from sour corn during- the last eight or ten years has 
been enormous, in some years being much more than in others. Thou- 
sands of dollars have been lost in a single year liy indivi<lual manufacturers 
who have ex])erienced this trouble. Moreover, the uncertaintx' and the 
possibilitv that losses may be incurred are constant sources of worrv and 
uneasiness to those engaged in this industrw 



DKTECTIOX UP SI'olLl-.l) CAXS. 

Spoiling in canned goods is generalK indicated by l)ulging of the ends 
of the cans, caused by the pressure of the gases procluced within. Thus a 
packer may generally detect any unsoundness before the goods are i)ut 
upon the market, as all are overliaftled and inspected before ultimate ship- 
ment. In tlie case of sour corn, however, at least in its first stages of de- 
terioration, ihcrc is no outward indication of trouble. It is onl\- under rather 
exceptional conditions that swelling occurs. If the temi)erature and other 
conditions are favoraljle for the rapid development of germs which can 
produce fermentation with the formation of gas. swelling will result. Since, 
however, the latter conditions rarelv ])revail in the factories, the detection 
of sour corn becomes difficult. Corn which is sweet when shipped may be- 
come sour many months afterward. To illustrate this fact an instance may 
be cited where from the same day's packing two lots of corn were shipped. 
-Hie to the northern and one to the southern i)art of the United States. That 
which was sent to the north was in perfect condition at the end of the year, 
while that which went to the warmer climate became sour in a short tiiue. 
Many instances of the same nature liave lieen noticed by different ])ackers. 
and similar results may be obtained by laboratory experiments, 'idie ex- 
planation of this fact probably is that all the bacteria were not killed by the 
lieating to which these cans were subjected, and that the conditions for 
growth of the micro-organisms became favorable only in the warmer 
locality. Provided sterilization is not complete, there seems little reason to 
doubt that climatic condition is a most important factor in the souring of 
corn. It should always be borne in mind that if processing or sterilization 
is comj^lete sour corn cannot result, because the germs of fermentation are 
destroyed. When souring occurs the percentage of bad cans tuay be small, 
but often runs from lo to 40 ])er cent., or even higher. Such goods are gen- 
erally returned, and an attempt is made to separate the sweet from the sour 
cans. To do this there are two methods in common use. 

According to the first method, the cans are put into a tank of water at a 
temperature of 80 dcg. 1-"., where thev stand for from six to twelve hours 
in order tliat the contents may be heated uniformly throughout. They 

33 



are then removed and their ends just submerged in water at 190 deg. F. 
Here they remain for not more than thirteen minutes. At the end of that 
time those cans which are swelled are rejected as sour. - The other method 
is to boil the cans for one hour. This causes all the ends to bulge. They 
are then cooled, and those whose ends remain bulged for more than eight 
hours are rejected, while those which "snap back" within this time are con- 
sidered satisfactory. Both these methods depend for their success upon the 
fact that at certain temperatures gas is produced rapidly by bacteria within 
the cans. 



BACTERIOLOGY OF SOUR CORN. 

Our investigations commenced in February, 1897, with the examination 
of a large number of cans of sour corn. On opening the cans no change 
was noticeable to the eye, the corn appearing fresh and of a natural color. 
In some cases a sour odor could be detected, but in others this was not ob- 
served. It was to the taste that the trouble was most apparent, the corn 
being sour and of a peculiar astringent quality. Bacteriological examination 
showed sound cans to be sterile, while spoiled cans invariably gave evidence 
of bacterial action. Pure cultures of twelve species of bacteria were ob- 
tained, of which eleven were bacilli, and one was a micrococcus. It must 
not be supposed that these bacteria are disease-producing; they probably 
act merely upon the saccharine and starchy matter, transforming it to 
organic acids and other substances of more or less disagreeable taste and 
odor, and make the corn unpalatable and destroy its commercial value. 

By inoculating sterile cans of corn with these organisms we have been 
able to produce souring in all respects similar to that of the spoiled cans 
from which they were originally taken. Our experiments were conducted 
in the laboratory in the following manner : A number of cans were selected 
and all of them were punctured, this operation being done in a sterile glass 
chamber. A part of the cans were inoculated with cultures obtained from 
sour corn, and all the cans were then sealed and put in an incubator kept at 
the blood heat. The cans which had been inoculated commenced to swell in 
from twelve to twenty-four hours, while those not inoculated remained as 
sound as when put in the incubator. Thus we easily proved that a vacuum 
is not necessary for keeping canned corn, and that air may be admitted to 
a sound can and spoiling will not result, provided proper precautions are 
taken that the air so admitted be free from germs. This statement will un- 
doubtedly be regarded with incredulity in some quarters, so strong is the 
popular belief among packers in the indispensability of a vacuum, yet a long 
line of experiments from the days of Tyndall to the present time prove the 
validitv of this assertion. Moreover, there are bacteria which can develop 
in a vacuum, and which could find favorable conditions within cans from 
which the air has been expelled. Sterilization, not the driving out of air, 
is the important factor in keeping all kinds of canned goods ; and although, 
as we have shown in our earlier paper, the vacuum is necessary in testing 

34 



the cans, no preserving power can be ascribed lo it. Tliese experiments have 
been made repeatedly, and always with the result that souring takes place 
when living bacteria arc present. The presence and activity of llie bacteria 
in sour corn have also been shown by inoculating various kinds of culture 
media with material from spoiled cans. Active fermentations, of the 
various kinds previously mentioned, have been brought about in this way. 
In order to study these fermentations more thoroughly, and to ascertain, 
if possible, the source of the bacteria causing them, we spent nearly the 
whole of the corn-packing season of 1897 at an establishment in Oxford 
County, Maine, where every convenience for scientific studv of the process 
was kindly put at our disposal by the proprietors. We were thus enabled 
to investigate thoroughly the methods of procedure, from the harvesting of 
the green corn to its ultimate shipment in cans. 



C0R.)f 



CANNING PLRNT5 



USUAL ARRANCigMENT OF PRINCIPAL 
MflCMINEBY IN MODERN WESTERN 

CORN CANNING PLANT3. 

CONTINUOUS AUTOMATIC SVgTEM. 




^ 



'^^ 



35 



THE PROCESS OF PACKING CORN. 

It is very impuriant that the utmost cleanliness and dispatch should be 
observed in all the operations, so that the chances of infection from bacteria 
may be reduced to a minimum. In this factory the strictest caution was 
exercised in these respects, everything being kept scrupulously clean. The 
corn is generally picked in the morning, and is delivered to tlie cannery as 
early as possible. One or two men make it their special duty to visit the 
farms once or twice a week during the season to keep informed as to the 
condition of the crop, and to "order in" the corn as it becomes sufficiently 
matured. As the ears are delivered at the factory they are arranged in low 
piles on the ground in an open shed to protect them from the sun. The 
husks and silk are taken off by hand, and the corn is then quickly carried to 
the cutting machines, in which, by a series of knives and scrapers, the 
kernels are <|uickly and cleanly separated from the cob. Any stray bits of 
cob or silk which may be mixed with the corn are now taken out as it passes 
through the "silker," a machine arranged somewhat on the plan of a 
gravel-sifter; that is, with two cylindrical wire screens one inside the other, 
placed on an incline, and rotating in opposite directions. The corn drops 
through the meshes of the screens, while the refuse passes out at the lower 
(open) end. 

The corn is now w^cighed, mixed with water in the proper proportions 
and is then ready for the cooker. There are several varieties of these ma- 
chines in use. all of which arc alike in principle, but differ somewhat in the 
details of construction. Their object is to heat the corn evenly and quickly 
to a temperature of 82-88 deg. C. (180-190 F.), and to deliver it automat- 
ically into the cans. A single machine fills about thirty cans a minute. The 
duty of the cooker is threefold : First, in the heating to which the corn is 
here subjected some of the bacteria, particularly those in the vegetative state, 
are killed. .*>ccond, the corn being filled into the cans while hot expands 
the air, so that after sealing and cooling a partial vacuum is produced, 
which, as before stated, is essential for the detection of unsound cans. 
Finally, this cooking heats the corn to such a temperature that the subse- 
quent sterilisation in the retorts is brought about more c|uickly, and the 
danger of browning or scorching of the corn next to the tin is minimized. 

The cans are next capped, soldered, and tested for leaks. Sterilization, 
the final and most important step in the whole process, now follows, and is 
done in retorts, by steam under pressure. The length of heating or process- 
ing, and the pressure which is given, vary somewhat in different factories. 
As we have shown in our previous paper, in practice, in order to insure 
sterilization it is necessary to obtain and maintain a temperature in excess 
of 100 deg. C. ( JiJ (leg. F. ) throughout the contents of the can and for a 
period of time varying with the substance to be sterilizefl. 

37 



Alodcrn canning machinery nsed in the process of packing green 
corn as mentioned in Professor Prescott's paper. 




SPRAGUE CORN CUTTER (l^ATEST IMPROVED. MODEL m) 



38 



Modern canning- machinery used in the process of packing green 
corn as mentioned in Professor Prescott's paper. 




TIIK <().Mm.\KI) ri.K.HV MKUUKl.t, SOl'LK CORN SILKER 



39 



Modem canning" machinery used in the process of packing green 
corn as mentioned in Professor Prescott's paper. 




THE MERREIjI^-SOULE DOUBLE CORN MIXER 




THE CUYKENDAIj CORN MIXER (COMBINED MIXER AND FEEDER) 

40 



Alodern caniiiiiLi- machinery used in the process of packing o-reen 
corn as mentioned in I'ro lessor Prescott's paper. 




TIIK lirit.MIAM (Oli.N (UOKKf! Kll.l.KH 




THK COXANT COnS CdOKKIl KFLLKU 



4f 



Modern canning- machinery used in the process of packing green 
corn as mentioned in Professor Prescott's paper. 




MEREELL-SOTILE CORN COOKER-FILLER 



42 




43 



Modern canning macliiner}- used in the process of packing green 
corn as mentioned in Professor Prescott's paper. 




THE WEST UPRIGHT PRESSURE PROCESS KETTLE OR RETORT 



44 



METHOD OF STERILIZATION. 

It is thought by smiic that intermittent sterihzation might be employed 
in packing, but we consider this entirely impracticable upon a coinmercial 
scale. Intermittent sterilzation consists in heating to the temperature of 
boiling water for a length of time varying from thirty minutes to one hour, 
on three or four successive days, the substance to be sterilized being cooled 
and kept cool between the heatings. It is supposed that in the first heat- 
ing all the active bacteria, the so-called vegetative cells, are killed, while 
the more resistant forms, spores, retain their vitality. According to the 
theory, the majority of the spores geriiiinate and become active before sec- 
ond heating, and in turn are killed, while by the third heating all the re- 
maining spores will have develoi)e(l into active bacteria, and will then be 
destroyed. 

To insure success by this method of sterilization, apparatus and means 
must be employed which, while practicable in a small way, are in our opin- 
ion absolutely impracticable on such extensive scale as would be demanded 
commercially. To use this method would necessitate at least three times 
as much sterilizing ap]iaratus. much more room, a greater amount of 
labor, and a great loss of time. 

To show the resistance of bacteria to the continuous action of a boiling 
temperature, we have found that certain species isolated from sour corn 
will survive actual boiling for more than five hours, and other species of 
bacteria which are met with in spoiled canned goods have been boiled for 
eight hours without being killed. These facts serve to show conclusively 
the impracticability of the ordinary water bath. On the other hand, the 
retort with its high temperature will, if properly used, kill all forms of 
bacteria at a single heating, without injury to the food substance, the 
length of time required varying, as has already been said, with the con- 
ductivity of the medii'tn for heat. We have found bv experiment that sixty 
minutes at 121 deg. (.". (250 deg. F.), as indicated by the thermometer on 
the outside of the retort, is sufficient time for sterilizing corn in two-pound 
cans, and it seems probable that this can be shortened somewhat, or the tem- 
perature reduced. I'urther experiments are in progress to decide this 
question. 

45 



WHITENESS OF CANNED CORN. 

Through a demand that canned corn shall be very light in color, there 
has been, apparently, a pressure put upon the packer to shorten the time of 
heating or to reduce the temperature in his retorts. The large losses which 
have resulted in recent years from sour corn have, it is claimed, been due 
principally to this demand. Instances are known where the desired result 
has been brought about by some bleaching reagent, generally sulphite of 
sodium. While this may not be unwholesome, it greatly injures the flavor 
of the corn, as a comparison of such corn with that without bleachers will 
show. Although such cases sometimes occur, it cannot be said to be the 
fault of the packer; for if the dealers demand very white corn the packer 
must resort to some unusual means in order to render his product salable. 
In this connection a statement in a recent trade journal is noteworthy : "The 
volume of poor corn which has found its way to market in the last few years 
has had, and is still having, a considerable effect upon the consumption of 
that article, and there are a good many families who never buy canned corn 
nowadays because they have found little but disappointment in their corn 
purchases of the last few years." 

It is much to be doubted if the consumer demands that the corn be very 
white in color. What he desires is a palatable article with a natural flavor. 
It seems evident that in the near future the dealers must regard this very 
white corn with disfavor, and reject anv in this condition. 



MAXIMUM TEMPERATURE WITHIN THE CANS. 

By the use of small registering thermometers which can be sealed up 
within the cans, and which record the maximum temperature reached, we 
proved, in an extended study of the process as it is actually carried on at 
the factory, that corn is a very poor conductor of heat, and that the time 
necessary to bring all portions of the center of the can to the requisite tem- 
perature is a factor whose importance cannot be overestimated. Corn as 
it comes in cans from the cooker is at a temperature of 82 to 88 deg. C. 
(180 to 190 F.). At the end of thirty minutes in a retort with a pressure of 
thirteen pounds, the corresponding temperature of which is 118.8 deg. C. 
(246 deg. F.), a thermometer in the center of a can placed in the middle of 
the retort, which was full of corn, registered 108.3 deg. C. (227 deg. F.). 
At the end of forty-five minutes, under the same conditions a temperature 
of 114 deg. C. (237.2 deg. F.) was reached and at the end of fifty-five min- 
utes the retort temperature of 118.8 deg. C. (246 F.) was registered by 



*Canner and Dried Fruit Packer, Vol. V, No. 19. 

46 



the thermometer in the can. From this it is evident that if a packer were 
o-iving- his corn an liour in the retort at this pressure, the central portions of 
the can would in reality be subjected to the full effect of the heat for only 
five minutes. Thus it is evident that with the present methods any reduction 
of time of heating is attended by considerable risk. If any means could be 
devised by which the heat could reach more quickly the center of the cans, 
it might be safe to shorten the time of heating. There is a prospect that be- 
fore long such modifications may be possible. 

BACTERIOLOGY OF SWEET CORN. 

The source of the bacteria producing the fermentations described was 
also a problem, the solution of which we sought with great care. Every 
step of the process was investigated bacteriologically, and all channels of 
infection, the water supply for example, were studied. The general cleanli- 
ness and the liberal use of water and steam throughout the factory which 
we visited reduced the liability of infection from dust to a minimum. We 
examined the green corn on the cob, the corn as it came from the cutting 
machines, as it went to the cooker, as it came from the cooker, and as it 
came from the retorts after the usual processing and after some periods 
of heating given for experimental purposes. Living bacteria were found 
on the raw corn, and at all stages of the process before the final sterilization, 
the corn as it went to the cooker was found to contain many germs, but in 
the short heating to which it was subjected there, some of the organisms 
were destroyed. Cans which had been retorted for thirty minutes or less 
were found to contain living bacteria, and cans so treated spoiled and became 
much distended within four days. No living bacteria were found in cans 
which had received the full time of processing at this factory. By cul- 
ture methods and by microscopical examination we have found that the 
bacteria living upon the kernels of corn and those which we found in the 
later stages of the process are undoubtedly of the same species. They all 
correspond in all respects with species which we obtained from cans of 
sour corn in the laboratory experiments carried on in the early part of our 
investigations. 

All these organisms are characterized by great rapidity of growth when 
allowed to develop at a temperature of 37 deg. C. (98.60 deg. F.). In evi- 
dence of this fact we need only to state that of the large number of cans 
incubated at this temperature many swelled within twenty-four hours, while 
in several cases the cans exploded within that time. Agar streak-cultures 
of these bacteria frequently showed well-marked growth within six hours, 
and in some cases in four hours. The growth is much retarded at a tem- 
perature of 20 deg. C. (70 deg. F.). None of the organisms which we have 
obtained correspond closely to the published descriptions of lactic or butyric 
acid organisms, or that of the Bacillus maidis of Cuboni. 

If sour corn is the result of bacterial action, the question naturally arises, 
Whv should a packer have trouble in a certain year, when he is using pre- 

47 



sumably the same methods of treatment that he has employed without loss 
in former years? A number of conditions might exist that would account 
for this. In the first place, it is a well-known fact that -diseases which are 
caused by bacteria may be much more prevalent in some years than in 
others. The same is probably true in the case of the bacteria which attack 
corn. The weather may be much more favorably for the growth of these 
germs in certain years than in others, and there is good reason to believe 
that a warm moist season is more apt to give sour corn than a cool dry one. 
Is the packer entirely sure that the conditions prevailing in the factory are 
always the same from year to year? Other things being equal, if exactly 
the same methods are used, similar results should be obtained. But to all 
outward appearances the conditions may be the same, when in reality they 
are quite dilTerent. Differences in the steam gauges or thermometers, or 
a little carelessness on the part of some operative, may be sufficient to turn 
the scale and give rise to sour corn where before none had existed. That 
trouble might be caused by such slightly changed conditions can be seen 
readily when we realize that, as we have already shown, it is being processed 
in the retort for an hour at a temperature of 240 deg. C, or over, the corn at 
the center of the can is in reality only receiving this intensity of heat for 
five minutes. 

Believing that, in order to be of practical value, all laboratory experi- 
ments must be carried on under conditions as nearly as possible like those 
existing in the factory, we have recorded only such results as have been 
obtained under these conditions. There are still some facts to be deter- 
mined which can not be settled by laboratory experimentation, and which, 
owing to the shortness of the packing season, we were unable to push to 
completeness last year. We hope another year to investigate these points 
more fully. 

We wish to express our gratitude and indebtedness to all those who have 
so kindly helped us. and particularly to Prof. Sedgwick, without whose co- 
operation this work would have been long delayed. 

In conclusion we would again affirm : 

1. That sour corn appears to be always the result of bacterial action, 
and due to imperfect sterilization. 

2. That in case of insufficient processing souring does not always re- 
sult unless the cans are subjected to conditions favorable to the growth of 
the bacteria within. 

3. That the bacteria which produce sour corn are found on the kernel? 
and beneath the husks of the corn as it comes from the field. 

4. That the bacteria found on the ears of corn correspond in all re- 
spects to those originally found by us in cans of sour corn. 

5. That swelling may be caused by bacteria other than those which 
produce sour corn, but it is always a natural consequence and a further 
development of this process of souring, provided the cans be subjected to 
a favorable temperature. 

6. That so far as we have been able to discover, the organisms present 

48 



in sour corn arc capable of producing serious commercial damage and an 
unpleasant taste, but are otherwise harmless. 

7. That a vacuum is not necessary for the preservation of canned goods, 
but is a valuable factor in the detection of unsound cans. 

8. That the use of bleachers is not to be recommended, and is unneces- 
sary if proper methods of sterilization be employed. 

9. That the utmost cleanliness at every step is absolutely essential. 

10. That intermittent sterilization is not practicable on a commercial 
scale. 

11. That the open water bath is incfihcient as a means of sterilization. 

12. That with the present methods of retorting it takes fifty-five minutes 
for the temperature which is indicated on the outside thermometer to be 
registered at the center of a two-pound can of corn previously heated in the 
cooker to 82 to 88 degrees C. (180 to 190 degrees F.). 

13. That heating for ten minutes with a temperature of 126 degrees C. 
(250 degrees F.) throughout the whole contents of such a can of sweet 
corn appears to be sufficient to produce perfect sterilization. 

Follow^ing the addresses members w^ere requested to ask any questions 
regarding the subject which interested them. This opportunity was eagerly 
taken advantage of and many important points were brought out. The dis- 
cussion being in every way pertinent to the subject, it is incorporated with 
the article : 

Mr. Bunting : Mr. Chairman, T would like to ask the gentlemen for the 
information of those present, when, in his opinion, bacteria take possession 
of corn. Of course, corn as it is plucked from the stalk must be in a healthy 
condition, and when it is husked it must be in its active, healthy condition. 
Now, sir. when, in your opinion, does bacteria make its first ap]K'arance to 
the detriment of the corn ; is it at the time the corn undergoes the cutting 
process and the milk is thereby exposed to the atmosphere, or is it prior to 
tiiat time? 

Mr. I'rescott : That is a hard matter to state, when they get there. 
You take the healthiest ear of corn that you can cut and subject the kernels 
to a bacteriological examination, you will find that in that case the kernels 
of corn have bacteria on them. When they get in I don't know. The seal 
of the husks, you know, is not absolute, and it may be that they are carried 
by moisture, and it may be that they follow down the silk and get in in that 
way. I think they are there probably all the time from the beginning of the 
development of the corn kernel. We do not only find these things in corn, 
but also in grain, in wheat. 

Mr. Bunting: When do they produce this? When does the souring 
take place? 

Mr. Prescott : That will take place in case the corn is packed rapidly, in 
case the heat in the matter of process is not strong enough to kill the spores. 
The spores have a formation resembling two husks, and when in this con- 
dition the spores rapidly shed one of the husks. They are covered by two 
coatings practically impervious to heat. Under favorable conditions they 
shed these coats rapidly and get into a vegetative form and then the develop- 

49 



ment is indeed very rapid. You put vegetative forms of these spores in corn 
and it will surely produce some souring. 

Mr. Black Did you make experiments with a less degree of heat than 
250 degrees? 

Mr. Prescott : We have made some experiments, but perhaps not so 
many as would be necessary to get an absolute figure as to what tempera- 
ture would be sufficient. 

Mr. Black : I understand corn is being processed all the way from 230 
to 250 degrees. Would anything less than 250 save the corn? 

Mr. Prescott : As you diminish the temperature you must increase the 
length of time of the heating. Our experiments indicate that corn is such 
a poor conductor of heat that in many cases, unless subjected to the limit or 
the time is increased, the temperature does not penetrate into the center of 
the can rapidly. Fifty-five minutes would be about the time necessary for 
the corn to be in the retort before the heat would penetrate to the center of 
the can. You cannot reduce the temperature unless you increase the length 
of time of the heating. The safest process would be with a heat of 250 de- 
grees. The outer cans liave a little freer access to the steam than those in 
the center. 

Mr. Black : Does that apply to dry steam or water process ? 

Mr. Prescott : That is dry steam . 

Mr. Black : Would not it be any different in water process ? 

Mr. Prescott : I should not suppose so. 

Mr. Bunting: The papers to which we have listened certainly must 
have proved interesting to all of us. We are all interested in the packing of 
corn. I am reminded by these papers of an accident which befell a friend 
of mine when packing in a shed a lot of corn green, it swelled and raised 
the roof off of the shed. These papers certainly have been interesting as 
well as instructive, and I move that this convention extend to these gentle- 
men who have entertained us this morning a vote of thanks. 

By the President : I want to say, before putting this motion, that the 
work of these gentlemen has been a work of love. While Mr. Underwood 
is a packer, he does not pack corn, and he has pursued these investigations 
merely from the pleasure of it, and in the hope that it would do somebody 
some good. 

(Motion put by the chair; carried.) 

By a Member: What effect has artificial preservatives upon bacteria? 

Mr. Underwood : It would have the effect of killing them, but it would 
be detrimental to the corn. We can kill all these things by heat. There is no 
need of using any preservative so far as that goes, in any canned goods. 
It should not be done, and it is not needed. I would like to state here that 
we have some cans of corn which we have inoculated and some which have 
not been inoculated. We should be glad to open these cans. We think 
we have some corn here that is sour in some of the cans in which the corn 
has been inoculated and kept in an incubator, and some that has not been 
kept there. Any questions yor might desire to ask we would be glad to 
answer. 

50 



Mr. Polk : Did you investigate to determine whether the corn would get 
darker by processing it at a degree of 240 ten minutes longer, than it would 
at the required time at 250? 

Mr. Underwood : It is rather hard to determine that. Every minute 
you add tends to darken the corn, and also every degree of heat. I don't 
just exactly get your question. 

Mr. Polk: I wish to know if it would become more dark to process it 
say ten minutes at 250 degrees than it would say twenty minutes at 240? 

Mr. Underwood : We haven't made any direct experiments on that sub- 
ject. I think the lesser time at 250 would darken it a little. 

Mr. Polk: Would different localities have an effect? For instance, in 
the west it requires a different cook than in the east. 

Mr. I'nderwood : I think that might be so. In the west you have warm 
weather. The way for the packer to do is to consider that the germs are 
in the cans and to make their retort time sufficient to kill them. It can be 
done easily. I understand there is to be a retort gotten up whereby the 
cans be subjected to the same degree of heat, and that heat will reach 
every portion of the can and the time can be shortened greatly from what it 
is now. If you give it a long enough time to get to the center of the can you 
are liable to scorch the corn near the outside of the can. 

Question : What would be the difference between a dry retort and 
moist retort ? 

Mr. Underwood : Our experiments have all been with the dry retort. 
The more water you put in the can the quicker the heat will go through it, 
and the less water you put in and the more dry corn in, the liarder to get heat 
into it. 

Delegate from Nebraska: If all the corn got a heat of 250 degrees for 
ten minutes, would that be sufficient? 

Mr. Underwood : Yes. 

Delegate from Nebraska : How long would it have to be kept at 240? 

Mr. Underwood : We haven't determined that yet. For instance, a 
can of soup could be processed in a very few minutes, because it is all water. 

Mr. Palmer: If the corn is packed very dry without any water at all the 
germs will not develop as much as if there was water in it. 

Mr. Underwood : Germs will develop much faster in moisture than in 
dryness. 

Question : From your experience, what is the minimum degree of heat 
that will kill these germs? 

Mr. Underwood : We will state that 250 degrees will do it. Somewhere 
between 2T2 and 250. The safety line may be between 250 and 212. We 
feel very certain that 250 is sufficient. 

Question : From what you have explained I should infer that a short 
hot dip would be much better than a longer one? 

Mr. Underwood : \'ery much. 

Question : I should infer from what you have stated that these spores 
develop under an increased degree of heat quicker than in the natural tem- 

51 



perature, and it is from the development of the spores that the trouble 
comes ? 

Mr. Underwood : Bacteria develop very much faster at the tempera- 
ture of blood heat than they do at a lower temperature. ^ Corn from one of 
the biggest packing houses was shipped, some of it south and some of it 
north. That that went south soured and that that went north did not. The 
reason for that is that these cans were not all placed under the same condi- 
tion, some having gone to a warm climate and some to a cold. 

Question : Are you satisfied that fifty-five minutes in a retort at 250 
degrees, that corn can be cooled down at once ? 

Mr. Underwood : I think that would be dangerous because it takes 
fifty-five minutes to get that heat there. The quicker corn is cooled after it 
is thoroughly processed the better, Fifty-five minutes at 250 degrees will 
thoroughly cook it. I think that is the danger line. You must understand 
we are not corn packers. 

Question : You contend that all corn contains bacteria ? 

Mr. Underwood : Yes. 

Question : Is it due to the acid in tomatoes that it is easier to save to- 
matoes than it is corn? 

Mr. Underwood : That is something we don't know anything about. 
Tomato is a liquid and the heat gets into the center of the can in a short 
time. 

Question : Would you advise the use of lime scattered around the 
factory ? 

Mr. Underwood : I think it would be a good idea ; and another thing 
I think would be a good idea is, and it is carried on in the factory where we 
were working making our experiments ; the cobs were taken away every 
night. As soon as they begin to ferment the air becomes full of germs and 
they are more liable to get into the goods. 

Mr. Bunting : What have you to say about brown corn, corn taken out 
of cook and allowed to cool without being submerged in water, is it more 
liable to become brown at one end ? 

Mr. Underwood: I think that would be a very natural condition. If 
you do not cool the corn the cooking is still going on. I have often noticed 
that the center of a can of corn is whiter than the outside. 

By a Member : Has the addition of sugar any bearing on the question of 
souring? 

Mr. Prescott : Cane sugar is not generally acted upon very rapidly by 
bacteria, so it does not seem that the addition of sugar would make any great 
difiference. There is no reason to think that the souring is due to the pres- 
ence of sugar in the corn. It does not seem to me that the souring would 
would take place any more quickly. 

By a Member: Would the heat of 250 degrees Fahrenheit have any 
eiTect on the spores in the corn? 

Mr. Underwood : It would kill them. 

Mr. Moore : I have known some packers of corn to have had one-quar- 

52 



ter of the pack sour without swelhng and the other be all right. How can 
that be accounted for? 

Mr. Underwood : Did the souring all occur in one place ? 

Mr. Moore: Yes, it ran through the whole pack. It did not come out 
of the retort at the same time. 

Mr. Underwood : Some i:)ackers use thermometers which are not at all 
fit to be used. Their steam gauges are often not right. Your thermom- 
eter must be thoroughly tested, that you must see to yourself. You don't 
know just what your men have done. Processing is the most important part 
in canning goods. If the thermometers are not exactly right your goods will 
not receive the proper process. 

The President : I think there is another explanation, and that is, every 
can of corn does not have the same amount of water put into it. Some 
cans are dryer than others and it might take longer for the heat to get into 
the center of the cans. 

Mr. Underwood: That is so; if everything is not just right, owing to 
the short time given to the processing, something wrong may occur. 

Mr. Bunting: Have you struck upon any plan whereby you can bring 
to light sour corn or peas that do not indicate their character on the surface 
of the cans and yet the conents are sour, a most vicious condition of things, 
of course ; have you struck on any plan whereby you can detect sourness in 
these cases so they may be thrown out ? We have given two methods for 
detecting those things. 

Mr. Underwood: If the right temi)erature is maintained there is no 
need of that. I think if we process our goods with the idea that the spores 
are naturally there there wall be no trouble. There is a way in which that 
might be done. In our experiments we have used an incubator and placed 
these cans in there. If a packer could fix up a room whereby he could main- 
tain a blood heat he could put in three portions of his pack every day and in 
the course of two or three days the sourness would be indicated by swelling. 
In years gone by my grandfather who packed and sold meat to the United 
States Government during the war of the rebellion had a room that he put 
his goods in; he put in part of his goods every day and in that way saw 
they were right before they were sent out. Something of that kind might 
"be arranged in regard to the corn. 

By a Member : Supposing we had a lot of corn that contained a per- 
centage of five or ten per cent of souring, would it be possible to subject that 
corn to 250 degrees to prevent any farther fermentation ? 

Mr. Underwood : It would stop those that were souring, but it would 
not turn those that had soured back into sweet corn. 

By a Member : Before sending them out, knowing there was a small per- 
centage, would it be safe, or could you save the balance by subjecting it to 
a temperature of 250? 

Mr. Underwood : Yes ; but it would have a tendency to darken the 
goods. You could overcome that by boiling them first. 

Mr. Bunting: What efTect has temperature upon corn? Now, we know, 
all of us, that the best corn ever packed in this country was packed years ago 

53 



when they used to pack it under a low temperature and cook it a long time, 
four or five hours. In those times you never used to hear of sour corn or 
dark colored corn. What effect has the pressure in the boilers on the cook 
of the corn? 

Mr. Underwood : It is not the pressure, but the extra heat "that is de- 
veloped by the pressure. 

Question : Have you done any experiments with corn that has been 
carried a long- distance and piled underneath the shed, as to whether or not 
that would increase the growth of germs? 

Mr. Underwood : We didn't try it, but it would naturally be so. 

The same Member : My only experience is that our loss has been greater 
from that source. Can this be killed by an increased heat ? 

Mr. Underwood : Yes, at 250. I don't think there is any doubt about it. 
I would recommend treating corn of that kind to an increased heat. 

By a Member: In carrying this heat would it be just as effective to 
carry 240 degrees for fifty minutes and the last ten minutes 250 degrees? 

Mr. Underwood: I couldn't say that. I think it would be necessary to 
carry it clear through. 

The President : Did you make any experiments with corn in different 
conditions? With corn that is very young and corn that has become hard- 
ened, to see whether the bacteria was present? 

Mr. Underwood : No, sir ; we haven't done that. We are going to do it 
another year. We did the most important things this last year. 

By a Member: Can you tell us why, since we have used bleachers for 
eight or ten vears without having any trouble, it begins to turn our corn 
black? 

Mr. Prescott : Have you made any change in the use of your plate ? 

Question : We began using American tin about the same time that the 
change took place. We have investigated along that line, but it was deter- 
mined by the chemists that that was not the cause. 

Mr. Prescott : If there is any difference in the quality of the plate the 
action of the sulphite of sodium on the iron would cause it. If the tin was 
off of the plate in any little place the chemical action of sodium on the iron 
would turn the corn black. 

Question : I have heard of this sulphide of sodium being used for some 
years, and have used it. A few years ago we had some trouble and I went 
back home and took an oath that I wouldn't use another grain of it, and I 
didn't use it, and the next year I had worse corn and more black spots than 
I had the vear before. The sulphide had nothing to do with it. The goods 
were worse that year than they were the year before, and I used nothing 
but salt and water in my corn. This was just about the time that I under- 
stood that Europe had sent to this country many boxes of tin and our home 
packers bought a lot of it at a cheap price and I came to the conclusion that 
the tin was so lightly on the plate that the acid in the corn caused these black 
spots. 

Mr. Prescott : Are the spots scatttered all through the corn ^ 

54 



Question : Sonictiiiios at the bottom, sometimes sifted all through, and 
sometimes in streaks. 

Mr. Prescott : Do you get it in the interior of the can? 

Question : No, sir. 

The President : I would like to make a statement in regard to the plate, 
and that is in late years they have been using less tin upon the plates than 
they used before, in fact, they use as little as they can. It is a fact now that 
tin plate makers in this country as well as in Wales are using in many 
cases two pounds of tin to make a box of loo pounds of plate. Of course, 
that is not good ])late and T have no doubt that the black spots may come 
from the action of the corn on the steel. 




IIKVOI.VINO CRATK OF THK AUTOMATIC C'AF.rir.M STSTKM (PATENTED) 

After attending the convention at which this paper was read. John C. 
Winters of Mount Morris. N. Y., commenced a series of experiments with 
the aim of improving the methods of processing to insure more uniform 
results in sterilizing and developed and perfected the automatic calcium 
processing apparatus (])atente(l). described on opposite page which not only 
reduces the cost of packing but removes to a very large extent the risk of 
souring spoilage and waste which occur in i)rocessing with kettles and 
retorts. 

55 



THE AUTOMATIC CALCIUM PROCESSING SYSTEM 

(Patented) 

referred to on preceding- page, takes the place of pressure process kettles 
and steam chests, for processing goods which require temperature above 
212 degrees Fahrenheit. 

It is claimed for this system that it reduces labor ; saves steam ; gives 
an absolutely uniform cook to every can of goods ; produces better results 
in color of corn and does away with all work connected with timing ket- 
tles. The contents of each can changes position repeatedly during the 
cook, thus insuring more uniform treatment. 

The System consists of a substantial boiler iron tank about 4^ feet 
wide, 4 feet deep and one foot in length for each thousand cans to be pro- 
cessed in ten hours. Above this tank is a support for endless chain trolley 
system, which carries hooks for engaging and dragging a cylindrical re- 
volving crate through a bath containing calcium in solution, heated by 
steam. Any temperature required (250 degrees in running corn) can be 
secured and uniformly maintained. The manner of operating this system 
is as follows : 

The Crate has a hinged gate opening along one side, into which the 
cans may drop directly from the discharge end of capping machine. At each 
end of the tank is a convenient power hoist. One operator hoists each 
crate as filled and hooks it onto the conveyer hooks. It then goes into 
and through the tank, the crate revolving as it is dragged slowly along 
by the carrier mechanism, which is set at desired speed, driven by a 
separate engine, furnished with the system for this purpose. When the 
crate emerges from the far end of tank an operator takes it with hook of 
power hoist, releasing it from the carrier hook, and lowers the crate into 
a small tank filled with constantly changing cold water. This rinses the 
can of the calcium. The processing is then complete. After rinsing, the 
hoist conveys the crate at right angles a few feet and it is there transferred 
to a second trolley system and is carried revolving through a second tank 
containing cold water. This tank is parallel to the cooking tank and its 
carrier driven from same movement as that of the processing tank. The 
cans are usually packed directly into canned goods boxes after they are 
dumped from the crate. 

With this system one foreman and three cheap hands is all the labor 
ret^uired to process and cool up to 80,000 cans in ten hours. 

56 



DESCRIPTIONS OF BACTERIA 

As Found by Professor Prescott and W. Lynuui L'nder- 
wood and Explained in Previous Chapters. 
Bacillus A. 
Found in Cans of Sour Corn. 
General characters : Shape and arrangement, bacillus, occurring singly and in 
short chains. Size: Generally 2-4U long by lu broad. Many cells are very long, and 
vary from 10-50U in length. Motility: Rapid serpentine and spinning movements. 
Relation to temperature : Develops at ZlV^ deg. C. ; more slowly at JO dcg. C. Re- 
lation to air : Aerobe and facultative anaerobe. Relation to gelatin : Liquefies. Color : 
Non-chromogenic. Gelatin: Stick culture; develops rapidly throughout whole length 
of puncture. Liquefaction begins within twenty-four hours, and at the end of two 
days a horn-shaped liquefied portion is observed. Plate culture: Surface colonies, 
very small. Liquefaction begins almost as soon as colonics are visible; in two days 




Plate Culture, Showing Colonies of Bacillus U. 
Found tmdcr husks of green corn. 

the plate culture is entirely licjuid. Submerged colonies, apparently same as on sur- 
face. Agar: Streak culture: A thin, smooth layer, covering nearly the whole sur- 
face. Edges dissected and bluish in color. In two days lower part of culture becomes 
dryer, white and finely wrinkled. Plate culture : Surface colonies : Vary much in 
size and shape. Young colonies are very small, oval or circular. Spreading soon 
begins, giving irregularly branched or sullatc colonies. Submerged colonies : Very 
small, oval or spherical. Potato: Potato much darkened. A thin film of growth 
covers the surface. This film is at first moist, but at the end of three days dry and 
finely wrinkled. Milk: Xot coagulated. Acidity, strong. Smith Solution: No gas 
produced. Thin film on surface. Sediment at bend of tube. Turbid throughout. 

57 



Strongly acid. Nitrate. Is reduced to nitrite solution clear. Bouillon : Slightly 
turbid at end of twenty-four hours at room temperature. Film develops in twenty- 
four hours in incubator at ziVi deg. No sediment. 

Bacillus B. 

General characters : Shape and arrangement : Bacilli, occurring singly and in 
short chains. Spore formation : Very small oval spores. Relation to temperature : 
Develop more rapidly at Z7V2 deg. C. than at 20 deg. C. Relation to air: Aerobic, 
facultatively anaerobic. Relation to gelatin: Liquefy slowly. Color: Non-chromo- 
genic, Gelatin : Stick culture : Growth well marked entire length of line of inocu- 
lation. A small cup-shaped depression is observed on second day. This increases 
in size as liquefaction occurs. 

Plate culture: Surface colonies: First appear as small translucent blue dots, 
which later become white or gray, and slowly liquefy the plate. Colonies from 1-8 
inch to 3-16 inch in diameter. Submerged colonies: Small and blue when seen by 




Bacillus U. Vegetative State From Bouillon. 
Magnified 1,000 Times. 

transmitted light. Agar : Streak culture : A thick, white, milky layer, covering the 
whole surface of the agar. The lower portion becomes somewhat wrinkled.. 

Plate culture : Surface colonies : Shiny, almost porcelain white in color, when 
about 1-32 inch in diameter often send out little branches of processes on one side, giv- 
ing a very characteristic appearance. Submerged colonies : Small, spherical dots. 

Bacillus C. 

General characters : Shape and arrangement: Bacilli, with rounded ends, occur- 
ring in chains. Motility : The chains swim with slow, steady, undulating motion. 
Spore formation : Large, oval, centrally located spores. Relation to temperature : De- 
velop rapidly at 371^ deg. C. ; more slowly at 20 deg. C. Relation to air : Aerobic 
and facultatively anaerobic. Relation to gelatin : Liquefy readily. Gelatin : Stick 
culture : Growth throughout, but most abundant at surface. A trumpet-shaped, lique- 

58 



fied portion is quickly formed, with rtocculcnt material in suspension and precipitate 
at ])Ottom. Film on surface. Plate culture : Surface colonies : At first white and 
small. As soon as they break through the surface liquefaction commences, and colo- 
nies rapidly become large and of a homogeneous gray color. At end of a week colonies 
are i inch in diameter and covered by a thin film, with concentric markings and fluted 
edges. Submerged colonies : Rcnmded and white. Soon break surface of gelatin and 
begin to liquefy. Agar: Streak culture: Thick granular layer, with dull luster. 

Edges sharply defined and scalloped. At the end of two or three days wrinkles 
appear on older portions. Plate culture: Surface colonies: Smooth and somewhat 
waxy in appearance. Often spread to form irregularly shaped patches with thickened 
edges. Submerired colonies : Small when separated, but often unite, forming a thin 
film on lower surface ot the agar. 

Bacillus I). 

General character: Sha])c and arrangement: Bacilli, occurring singly and in 
chains. Motility: Chains imt nnuile. Single cells move with slow serpentine motion. 




Bacillus U. Vegetative State From Agar. 
Magnified i,ooo times. 

Spore formation: Spores formed in center or near one end. Relation to tem- 
perature: Develops rapidly at 37' j dcg. C. Relation to air: Aerobic and faculta- 
tively anaerobic. Relation to gelatin: Liquefy. Gelatin: Stick culture: Growth 
slight, but noticed throughout. Liquefaction soon begins. Plate culture: Surface 
colonies: First appear as white dots. Liquefaction begins quickly, and a liquefied 
saucer-shaped depression, with a white dot at center, is soon formed. Colonies rap- 
idly become large, and have flocculcnt precipitate near center and finger-like processes 
projecting inward from edges. At end of a week the plate is nearly all liquefied and 
a tliin film is developed at surface. Submerged colonies: Few and small. Agar: 
Streak culture: Thick, slimy growth readily removed. It occurs in form of scal- 
loped patches, with smooth edges. Plate culture: Surface colonies: White or 

59 



gray, regular in outline, and smooth and shiny when young. Later become somewhat 
irregular in shape. Submerged colonies : First appear like woolly or burlike rounded 
masses, which soon break through surface and become shiny and smooth, like surface 
colonies. 

Bacillus E. 
General characters : Shape and arrangement : Long, narrow bacilli, generally 
occurring singly. Very variable in size. Motility : Move rapidly, with eccentric dart- 
ing and twisting movements. Spore formation : Small, oval centrally located. Rela- 
tion to temperature : Develops rapidly at y7y2 deg. C. ; slower at 20 deg. C. Relation 
to air : Aerobic and facultatively anaerobic. Relation to gelatin : Non-liquefying. 
Gelatin : Stick culture : Slight spreading growth at surface, and growth all along 
line of inoculation. Filmy, ragged surface. Growth at end of second day. Transpa- 
rent. Plate culture : Surface colonies : circular ; bluish by transmitted light. Grow 
to about 1-8 inch in diameter. Submerged colonies: Small white dots, developing 




Bacillus U. Spores. 
Magnified 1,000 times. 

more slowly than surface colonies. Agar : Streak culture : In growth very similar 
to A. Bluish edges, finely dissected. Surface of Agar covered with a thin, white 
layer, finely wrinkled at the base. Plate culture : Surface colonies : At first small 
rounded masses, which on the third or fourth day show a thin surrounding outgrowth 
appearing bluish by transmitted light. Submerged colonies : Many small colonies 
about size of pin points. 

Bacillus T. 
General characters : Shape and arrangement : Rods occurring singly in short 
chains. Motility : Slightly motile. Spore formation : Oval spores, filling nearly the 
whole cell. Relation to temperature : Develops more rapidly at 37.5 deg. C. than at 
20 deg. C. Relation to air : Aerobe and facultative anaerobe. Relation to gelatin : 
Liquefies. Gelatin : Stick culture : Development all along line of inoculation in 

60 



twenty-four hours. Liquefaction takes place, forming a trumpet-shaped mass, some- 
what depressed at surface. A fihii develops on surface, and a flocculenl substance is 
held in suspension . Plate culture : Surface first appear as small spots. Soon lique- 
faction begins, forming a cup-shaped depression, with a central, whitish mass. At 
end of a week a thick, waxy scum, marked by concentric rings, covers the entire sur- 
face. Agar: Streak culture: Thick, gray film, with irregular edges. Dull, granular 
mat surface on lower portion, an.i smooth and lustrous above. Plate culture : Sur- 
face colonies: Grayish or brownish in color, irregular in outline. Thickened edges; 
sometimes a dot is seen at center. Submerged colonies : Like surface colonies in 
general appearance. 

Bacillus Y. 
General characters : Shape and arrangement : Stout, thick rods, occurring singly 
and in chains. Motility : Slow, serpentine motion ; chains also motile. Spore forma- 




Plate Culture, Siiowing Colonies of Bacillus U 
Found in Cans of Sour Corn. 



tion : Oval spores. Relation to temperature: Develops umre rapidly at yjYi deg. C. 
than at 20 deg. C. Relation to air : Aerobic and facultative anaerobic. Relation to 
gelatin : Liquefies rapidly. Gelatin : Stick culture : Growth throughout in one day, 
and liquefaction already begun at surface; much increased on second Jay. and tloc- 
culent precipitate in Imver lart of liquefied portion. Gelatin finally becomes entirely 
liquid, and have sediment formed. Plate culture: .Surface colonies: Circular and 
rapidly liquefying; soon become covered with film. Saucer-shaped depression formed, 
at center of which is a llocculent. suspended mass, surrounded by ring of clear h'quid. 
Submerged colonies: Small and inconspicuous. Agar: Streak culture: \'ery thick, 
much-wrinkled layer, white and somewhat shiny. Edges finely scalloped. Plate cul- 

61 



ture: Surface colonies first appear as small dots; later form irregular spreading 
growths of varying thickness. Submerged colonies : Thin, blue, irregular in outline. 

Bacillus Z. 

General characters : Shape and arrangement : Bacilli, occurring singly and in 
long chains. Motility : Moves with slow serpentine motion. Spore formation : Small, 
oval, centrally located spores. Relation to temperature: Develops rapidly at 37^/2 
deg.'c. ; more slowly at 20 deg. C. Relation to air: Aerobic and facultatively anaero- 
bic. Relation to gelatin : Liquefying. 

Gelatin : Stick culture : Growth throughout and liquefaction at surface at end of 
first dav. On second day liquefaction has spread to walls of tube, a wrinkled film was 




Bacillus W. 
Magnified 1,000 times. 

present on surface, and flocculent precipitate in suspension. Plate culture: Surface 
colonies develop rapidly. When about 1-16 inch in diameter liquefaction begins. A 
central area of flocculent material is present. At end of a week colonies are large, and 
are covered by a thick film of waxy appearance and showing concentric rings. Sub- 
merged colonies : Small. Agar : Streak culture : A thick, white layer, of rather dull 
luster and finely granular appearance, covers the wliole surface of the Agar. Plate 
culture : Surface colonies : Irregular in outline, slightly thickened at the center. 
Brown and somewhat shiny. Some colonies show irregular outgrowths and appear 

62 



woolly. Submerged colonics : Spread or. lower surface of Agar, forming a thin layer, 
which appear bluish by transmitted light. 

Bacillus S. 

General characters: Shape and arrangement: Bacilli, generally occurring singly, 
but frequently in chains of three or four. 

Motility: Quick swinnning motion ; chains also motile. Spore formation: Small, 
oval, centrally located spores. Relation to temperature: Develops more rapidly at 
ZlV^ deg. C. than at 20 deg. C. Relation to air: Aerobic and facultatively anaerobic. 
Relation to gelatin: Liquefies rapidly. Gelatin: Stick culture: Growth throughout 
in twenty-four hours. Liquefaction at surface. Thick film, marked with concentric 
rings on surface. At end of a week liquefaction extends to walls and \\ inch down 
from surface. Plate culture: Surface colonies at end of two days are small, and 
white or bluish in color. Li(|uefaction begins about the third day. and proceeds slowly 




Plate Cu.lturc. Showing Colonies of Micrococcus 
Fourd untltM" husks of green corn. 



X. 



until the whole plate is liquid. Colonies form saucer-shaped depressions with a central 
disk of gray and sharply defined edges. Submerged colonics : Small, irregular, and 
hazy in outline. Agar: Streak culture: A thin, smooth, shiny, transparent layer, 
with bluish color and scalloped edges, covering nearly the whole surface. Plate cul- 
ture: Surface colonies first appear as small, round, white spots. Spreading soon 
begins, and stellate or branched colonies, with bluish fluorescence are formed. If many 
colonies are present on the plate the branching is less conspicuous, and the plate soon 
becomes covered with a thin layer. 

Bacillus \5. 
General characters : Siiapc and arrangement : Rods occurring singly and in 
chains of two or three elements. Motility: Rapid, serpentine and spinning motion. 

63 



Spores formation : Oval spores formed. Relation to temperature : Develop rapidly at 
ZIV2 deg. C. ; more slowly at 20 deg. C. Relation to air : Aerobe and facultative an- 
aerobe. Relation to gelatin : Liquefy. 




Micrococcus X. Taken From Above Colonies. 
Magnified i.ooo times. 




Plate Culture, Showing Colonies of Bacillus W at End of Forty-eight Hours 
Found in cans of sour corn. 

64 



Gelatin: Stick culture: At end of first day faint growth along needle track. On 
second day sliglitly liquefied at surface. Liquefaction spreads rapidly to wall of tube, 
and whole upper portion soon becomes liquid. Plate culture : Surface colonies : When 
very small show slight branching, but as soon as liquefaction begins colonies become 
circular and form depressions in the gelatin. Plates become entirely liquid in a few 
days. Submerged colonies : Small, spherical and inconspicuous. Agar : Streak cul- 
ture : Smooth, white, shiny layer, with branched or serrated edges, and extending 
over nearly the whole surface. Plate culture : Surface colonies : Circular when 
very young, but branching takes place as colonies develop, producing stellate forms. 
The fewer the colonies the more marked the branching. 




Plate Culture, Showing Colonics of Bacillus W at End of Twenty-four Hours. 
Found in cans of sour corn. 



Bacillus \V. 

Genci-al character: Shape and arrangement: Stout rods, rounded ends, generally 
in chains. Motility: Swim rapidly with undulating motion. Spore formation: Oval 
spores centrally located. Relation to temperature: Develops rapidly at 37'/'2 deg. C. : 
slowly at 20 dee. C. Relation to air : Aerobe and facultative anaerobe. Relation to 
gelatin: Liquefies rapidly. Gelatin: Stick culture: Development well marked at 
end of twenty-four hours. On second day a large trumpet-shaped mass of liquefied 
gelatin is formed, in which is suspended a heavy flocculent precipitate. Plate culture: 

65 



Surface colonies : Circular, rapidly growing, and containing a gray or brown precipi- 
tate at center, surrounded by a broad ring of clear liquefied gelatin. On long standing 
surface becomes covered with a thin, scaly film or incrustation. Submerged colonies: 
Small, circular or oval. Agar : Streak culture : A thick, fiije granular layer, with 
bluish irregular and indistinct edges, covering nearly the whole surface of the Agar. 
Plate culture : Surface colonies : Granular, brownish-gray colonies, of rather dull 
luster, irregular in shape and thickened at the edges. Young colonies appear somewhat 
finely branched or woolly. 

Micrococcus X. 

General characters: Shape and arrangement: Micrococci, occurring singly and 
in irregular clusters. Motility: Not motile. Spore formation : Not observed. Rela- 




Plate Culture. Showing Colonies of Bacillus W at End of Twenty-four Hours. 
Found under husks of green corn. 



tion to temperature: Develop well at 37^ deg. C. ; slowly at 20 deg. C. Relation to 
air : Aerobic and facultatively anaerobic. Relation to gelatin : Does not liquefy. 
Gelatin : Stick culture : Development : Slow ; growth throughout somewhat raised 
at surface, forming a small button-like mass. Plate culture: Surface colonies: 
Sharp outline, raised above surface concentric markings, bluish white in color, and of 
somewhat waxy luster. Submerged colonies : Small, spherical. Agar : Streak cul- 
ture : Growth closely follows line of inoculation. Bluish white, semi-translucent, lus- 
trous and moist. Plate culture : Surface colonies : Circular and somewhat dome- 
shaped. White in color. Develop in shout three days. Submerged colonies: Small, 
oval or rounded. 



66 



CHAPTER 111. 

At the annual convention of the Atlantic States Packers' Association and 
the Western i'ackers" Canned Goods Association, held at Detroit in February, 
1899, Professor I'rescott and Mr. \\'. Lyman Underwood were again engaged 
to deliver papers covering their experiments, following their report of the 
previous year at Buffalo. 

Professor I'rescott was first introduced, and spoke as follows : 

THE CAUSE AND PREVENTION OF SOUR CORN. 

The question of preservation of food is at the present time one of the most 
interesting and important in the whole held of applied science, and we cer- 
tainly regard ourselves as fortunate in being again asked to speak before 
an assembly of those who have so vital an interest in this subject. The 
events which have transpired since we had the pleasure of addressing the 
Buffalo Convention a year ago have only made more evident and more im- 
pressive the necessity for sure and safe processes of food preserving, and 
for more accurate knowledge regarding these processes of food preserving, 
and for more accurate knowledge regarding these processes. 

So, in accepting your president's courteous invitation to speak on cer- 
tain phases of the general subject, we feel that perhaps w^e can do no better 
service than to begin by briefly considering some of the facts that find 
application in all branches of the industry. All kinds of canned goods, 
so far as we are aware, are liable to undergo fermentative or putrefactive 
changes unless some means are taken to guard against such action. I 
would like, first, to speak of the causes which lead to these troubles. In 
the early days it was believed that the access of air was responsible, but as 
can be easily demonstrated by a simple experiment, this view was fallacious 
and we must seek further for the true cause of decomposition. The view 
at present held by intelligent and observing people is that these changes 
are brought about by the activity of very minute living things which we 
commonly and popularly speak of as germs, microbes, micro-organisms, 
or bacteria. All these terms are used somewhat indiscriminately, and 
all mean practically the same thing. 

67 



At the outset, I would like to caution you against a very widespread 
belief that all bacteria are disease-producing in their nature. As a matter 
of fact, the useful germs greatly outnumber the harmful ones, as the use- 
ful citizens of the community outnumber the criminals. Perhaps I can- 
not make the contrast more convincing than by stating that there are now 
on the market preparations of bacteria which are used in the ripening of 
cream, in the production of flavor in butter and for the increase of fertil- 
ity in the soil. In fact, without the action of bacteria, we could not exist, 
so we must regard them as friends rather than foes, even though there 
are a few species which might do us injury. That the majority of them 
are harmless is evident from the fact that with every glass of water we drink 
we take in hundreds of them, and they are present in ordinary milk in 
great numbers. The upper layers of the soil abound in them. In fact it 
is difficult to find many places where they are not present. 

From what I have said of their abundance, one may perhaps get an 
inkling as to their size. This may be best realized, I think, by some com- 
parisons. 

(Mr. Prescott here showed charts and models of several kinds of bac- 
teria magnified 50,000 times.) 

A yeast cell magnified 50,000 times would be about as large as a foot- 
ball ; a man magnified in the same proportion would be about fifty-four 
miles high and his hand about three miles broad. We might regard a 
bacillus one twenty-thousandth of an inch in length as perhaps an average 
sized organism, while some of the largest ones might be one four-thou- 
sandth of an inch long. 

The shape of these organisms may be classified as spherical like a ball, 
elongated like a lead pencil, or spiral like a corkscrew. These are the type 
forms and we get all gradations between them. Then, too, we find dif- 
ferences in the way in which they are arranged, sometimes being arranged 
singly, sometimes growing into long chains or threads and sometimes sim- 
ply forming irregularly shaped groups or clusters. 

We do not find these little plants complex in structure, made up of nu- 
merous organs, but rather they are very simple, being composed of a single 
cell. On account of the very small size, we are unable to state very definitely 
about the structure, except that they have a thin membraneous covering 
like a sausage, but as in the case of the sausage also, we do not know what 
may be inside. 

By proper means we can cultivate the bacteria, and observe the changes 
which they bring about in various media, and it is by such cultures, as 
they are called, that we learn of the nature of each particular kind of bacte- 
ria, and the chemical reactions which it will induce. On certain kinds of 
media we get the appearance of circular or branching spots known as col- 
onies, each colony developing from a single germ. It is only when col- 
lected in such large masses, containing thousands or millions of individuals, 
that they become visible to the naked eye; to observe the single germs 
requires the high power of a microscope. Often they are seen in lively 
motion. When actively growing, or as we say, in a vegetative condition, 

68 



the process of rei)roduction goes on with great rapidity, each germ divid- 
ing into two, these into four, and so on, thus in a few hours giving rise to 
vast numbers. Under favorable conditions this spHtling of one germ into 
two may take place as often as once in twenty or thirty minutes, which 
at this rate would give rise to billions in the course of ten or twelve hours 
unless their own products of growth were sufficient to check the repro- 
ductive process, it is when in this vegetative state that the bacteria are 
most active, and bring about their decompositions with the greatest 
rapidity. 

Perhaps of greater importance, from the point of view of the canner, 
are the more resistant forms known as spores, which are modifications of 
some of the rod shaped bacteria, enabling them to endure hard times or con- 
ditions unfavorable for development. When in this condition they can 
live for months apparently dead, but awaiting to develop again into actively 
vegetating forms as soon as the conditions become favorable. When in 
this condition also, the bacteria are much more difficultly killed by the ac- 
tion of heat, hence they are a continual source of trouble to the packer unless 
he is certain that his process is sufficient to kill them. While ordinary 
vegetating liacteria are readily killed at the temperature of boiling water, 
or even by comparatively short heating- at temperatures below boiling, 
the spores will frequently withstand several hours of boiling. It is not 
uncommon to hnd spores which can be boiled for five hours and remain 
uninjured. Some forms can endure much more than this, and we have 
found some in our work that are not killed by boiling for eight hours con- 
tinuously. It is then obvious that simply boiling for a short time does not 
offer a very sure means of processing. If no spores are present there may 
be no trouble, but owing to the abundance of the bacteria, we should always 
bear in mind that spores may be present and so formulate our process 
accordingly. 

Although so Impervious to the heat of boiling water, the spores are killed 
by increased heat, as for example, by steam under pressure ; the more 
intense the heat the less time can the spore endure. This then is the true 
reason why retorts or kettles in which steam under pressure is used have 
so largely replaced the water baths. This will be treated more fully by Mr. 
Underwood. 

I have already mentioned the rapidity with which bacteria develop. It 
is, however, only when conditions are favorable that we find this action 
going on with such marvelous speed. We may regard as favorable con- 
ditions warmth, moisture, and a plentiful food supply. The substances 
which serve as food for us are excellent food for the bacteria, so that when 
present in canned goods they are generally in a most favorable environ- 
ment. There is a wide variation as to the temperature which will allow 
development, but in general, low temperatures exert a restraining inlluence, 
while at blood heat the activity is much increased. Since the germs take 
in their food by direct absorption through a cell membrane, moisture is 
essential to their well-being, and the preservation of food bv drving de- 
pends upon this fact, as in a dried state the germs can get no foorl and so 



69 



are inactive. As soon as the amount of moisture becomes sufficient, how- 
ever, they immediately begin to propagate. 

But perhaps the most interesting facts about these germs are not re- 
garding their size and shape, but deal rather with their abilities to act 
upon organic materials of manifold varieties, changing them into other 
substances lower in energy and sometimes of an entirely different nature 
from the original substances. So well-defined are some of these processes 
that we might almost regard bacteria as chemical reagents, which when 
added to a fermentable or putrescible material, give rise to definite com- 
pounds of various kinds. This action which is brought about only by the 
vegetating germs forms a part of the functions of the organism just as 
much as our own processes of digestion and absorption constitute a part 
of the work of our own bodies. The spores themselves being inactive must 
go through a process of germination as we say, in some respects similar 
to the germination of a seed, before they can carry on these changes. In 
this germinating process the tough, resistant outer coating of the spore is 
ruptured or entirely cast off, and an active vegetative cell emerges. This 
process of spore germination only takes place when the conditions become 
favorable for the growth of the normal or vegetable cells. This may account 
for some cases of spoiling which appear to be belated, or which, perhaps, 
do not appear until spring time, or until the cans are put into a warm place. 
Then the chemical changes and the multiplication of the bacteria go on 
side by side until perhaps the substances formed are present in such an 
amount as to prevent further development. 

All these chemical changes brought about by the activity of the bacteria 
and other micro-organisms like yeast and moulds may be grouped together 
in a class to which we apply the fermentation. This term, although origin- 
ally used to designate the change brought about by yeast in which a sugary 
liquid like a fruit juice is changed to an alcoholic one, is now used in a 
much broader sense, including the changes from cider and wine to vinegar, 
the souring of sweet milk, and the transformation of sugars into various 
acids, and the breaking down of various complex substances into simpler 
ones. It therefore includes the changes which are brought about when 
canned goods undergo deteriorations caused by bacteria. 

These fermentative changes can be prevented in two ways. First, by 
sterilization by heat, by which we mean that all bacteria, whether in a spore 
state or vegetative state, are subject to such a temperature that they are 
killed outright and therefore rendered inert. This is the general principle 
underlying all canning operations, and is the only sure and safe one to fol- 
low. Or, we may prevent these putrefactive or fermentative changes in 
another way, that is, by the use of antiseptics. By an antiseptic, we mean a 
substance which does not necessarily kill the germs, but restrains or pre- 
vents their development. Growth may again take place, however, if the 
restraining influence is removed. The use of antiseptics has many disad- 
vantages, and notwithstanding the fact that opinions as to their unwhole- 
someness vary, there seems to be no reasonable excuse for the use of an 
antiseptic in any food preparation. An objection which cannot be too 

70 



strongly presented is that substances which are injurious to bacteria are 
also in general likely to be injurious to the human organism. Moreover, 
the presence of even small amounts of preservatives frequently gives an un- 
pleasant and unnatural taste to canned goods. 

In some states, as, for example, in Massachusetts, the laws regarding 
adulterations in foods and the use of antiseptics are stringent and well- 
enforcefl, as it is the desire of the Commonwealth to protect the health 
of citizens in so far as possible. Had there been any national law of this 
kind, we should probably not now be undergoing the deplorable war in- 
vestigation. 

In my foregoing remarks 1 have tried to make clear the facts that fer- 
mentation or spoiling in can goods in general is brought about by bacte- 
rial action and that the bacteria may be in a vegetative slate or a more re- 
sistant spore state, but that in either case they may be destroyed by proper 
heating. Aside from these general considerations, it is obvious that, on 
account of the very numerous and widely ditt'erent varieties of canned foods, 
the more specific rules which apply in one case may not at all fit another 
case, but that each product must be treated separately. 

Bearing this in mind, I wish now to consider more in detail the subject 
of the fermentation of sweet corn, or as it is better known to the packing 
trade, the production of sour corn. When this occurs a change is brought 
about by action of bacteria wliich were not killed in processing. These 
bacteria belong chiefly to the lactic acid group, that is, the general change 
is similar to that brought about in the souring of milk. In each case we have 
a sugar acted upon by the bacteria and split at once into an acid. In both 
cases lactic acid is the principal one formed. In addition to the lactic acid 
there are frequently produced in the corn small amounts of other acids, as 
acetic, formic and butyric and other products of fermentation. Gases, as 
carbon dioxide and hydrogen, may sometimes be produced in considerable 
amounts, particularly if the temperature be not too low, and in that case 
a "swell" is the result. At low temperatures gaseous products may be 
formed but at once dissolved in the liquid within the can, thus giving no 
swelling until the can is warmed so that the gas is driven out of solution. 
Or we have another variation of this fermentation taking place in which 
the amount of gas evolved is very small, but almost the whole energy of 
the bacteria is used in splitting the sugar into lactic acid. This would 
take place when food conditions are most favorable. This would give 
sour corn without swelling. This, however, is not the only case of spoil- 
ing without swelling, as the same thing occurs with many other products 
when the processing is insufficient, notably "black lolistcr." which has 
caused tremendous losses. These dififerent modifications of the same fer- 
mentation are brought about by slight differences in the conditions, or per- 
haps by slight differences in the physiological activity of the germs. We 
may also note differences in a fermentation according as it proceeds with a 
plentiful supply of air. or without the access of free atmospheric oxygen. 
In the latter case, the oxygen necessary for the further multiplication and 
for the food of the organisms must be obtained by breaking down some of 

71 



the substances in the corn, and in this process gases are generally evolved. 
As there is no likelihood that merely a single species of germ is present, 
especially when the action is in its early stages, we get, a most complicated 
set of fermentations taking place, in all of which the chief product is an acid. 
Later, one species of bacteria may develop at the expense of the others, 
and the acidity produced will probably increase as the temperature is in- 
creased. 

The sugar most rapidly split up by the bacteria is glucose, and undoubt- 
edly the sweetness of young corn is due for the most part to this compound. 
In older corn, it is changed to starches and a little cane sugar, but in the 
heat under pressure to which the corn is subjected, these starches and 
sugars are doubtless hydrolised, that is, they unite with water and form glu- 
coses again. This process is not necessary, however, as the bacteria them- 
selves can frequently bring about this change. Aside from the carbo- 
hydrate food there is no reason why fermentation should not take place if 
the germs are present as the water and nitrogenous substances necessary 
for the bacteria are present in abundance. 

In addition to the recognition of this acid by taste or smell, it can be very 
easily demonstrated by chemical means, in fact, it might even be detected 
when in such small quantities that there is practically no sour taste. 

(Mr. Prescott here showed by an experiment how the acid in corn could 
be detected.) 

The possible sources from which the bacteria might get into the cans 
of corn may perhaps be briefly discussed. There are five principal sources 
from which infection might occur. 

1. From the corn itself. 

2. From handling, and utensils in use. 

3. From the air. 

4. From the water supply. 

5. From the syrup or brine. 

Regarding the first three of these sources I shall say nothing, as they 
will be mentioned in the second part of our paper. The question of 
water supply, while it should not be neglected, does not have as great 
significance here as in some other manufacturing processes. It is, of course, 
desirable to have a good water supply. The number of bacteria in water 
varies according as a well or surface supply is used and according to the 
amount of organic matter present. The bacteria present in normal water 
are generally very readily destroyed at a boiling temperature, and many 
of them are killed at lower temperatures. Any spore forming bacteria 
would be killed in the final process as very resistant water forms are rare. 
Therefore, we may dismiss the question of water supply as relatively 
unimportant in general, although it should be borne in mind that a water 
supply might become so infected as to be a menace to the packer. 

As it has been suggested that the syrup or brine used in the corn might 
perhaps be a source of infection, we have made some very careful ex- 
periments, using the components in the same proportions as would be used 

72 



in actual canning operations on a large scale. We first took up the case 
of cane sugar. 1 went to a sugar refinery and obtained samples of va- 
rious raw sugars and refined products. We first studied these bacte- 
riologically, subjecting them to quantitative examination, and then making 
an investigation to find out if solutions of these sugars would support 
bacterial life. In the poorer grades of raw sugar we found bacteria to 
be present in considerable but not great numbers. Moulds are also quite 
numerous. The higher gratle raw sugars, both cane and beet, contained 
few bacteria, and tlie refined product was practically free from germs. 

The raw sugars, when dissolved in sterilized water and allowed to stand, 
showed a rapid increase in the number of bacteria, demonstrating that 
they would support bacterial life. In the refined sugar, on the other 
hand, there was apparently no increase, thus showing that in the process 
of refining the germs are destroyed. 

Pure cane sugar is not generally regarded as a good food for bacteria, 
yet our results showed that when nitrogenous matter is present in small 
amounts a five per cent solution of cane sugar will support bacterial life. 

Our next experiments were made with the brine of the same compo- 
sition as that used for corn. Sterilized brine was inoculated with bac- 
teria derived from sour corn, and put into an incubating chamber at the 
blood heat. Development occurred, but in only limited amount, and thus 
far we have obtained no evidence that bacteria will develop rapidly in 
brine, particularly as the salt present exerts a restraining influence. The 
result of our work, however, showed that slight development might occur, 
therefore, we must emphatically assert that brine should never be allowed 
to stand over night, and that the utensil holding the brine should be care- 
fully washed out with boiling water each day. Unless these precau- 
tions are taken, there is the possibility that genns might develop during the 
night, form spores, and so infect the whole of the next day's pack. Of 
course, with proper processing these spores would be killed, but if the 
retorts were running close to the danger line this would be less likely to 
happen. 

The brine used in the foregoing experiments was made with sugar as 
the sweetening substance. As saccharin is frequently used for this pur- 
pose, we have made some investigations as to its relation to bacterial de- 
velopment. Saccharin 'is a coal tar product containing carbon, hydro- 
gen, nitrogen, oxygen and sulphur, and in the pure state has a strong 
acid reaction. Probably on this account the statement is made that it is 
antiseptic in its action, and hence better to use than cane sugar on this 
account. We first studied the antiseptic power of saccharin. A strong 
solution was made which was neutralized by the addition of sodium bicar- 
bonate as is directed in the rules for use. This strong solution was used 
as a basis, and from it more dilute solutions were prepared. The strong 
solution contains about three per cent, saccharin by weight, and for the 
tests under consideration, it was used full strength and also diluted in 
the following proportion: i to 2, i to 4. i to 8, i to 10. i to 20, i to 50. 
and T to TOO. To these solutions, in flasks, was added a small amount of 

73 



nutrient substance and a culture of bacteria. The bacteria used in these 
tests of antiseptic value were some of the germs originally found by us 
in sour corn, thus making the examination of particular interest. 

If saccharin was strongly antiseptic we should expect to find no growth 
appearing in the flasks when it was present. We found, however, that 
such was i)Ot the case. All the fiasks showed some growth, but in those 
containing the strong solution there was much less than in the weaker 
solutions. In the latter there was practically no restraining influence 
at all. 

These results show conclusively that the antiseptic or preserving power 
of saccharin has been very much overestimated. As the weakest solution 
used in our experiments contained about three times as much saccharin 
as would be in syrup or brine it is evident that it has no preserving power 
when used in this way. Indeed there seems to be some ground for be- 
lief that it would increase the bacterial food contents of the corn. Our 
results would indicate that compared with cane sugar the latter has the 
greater preserving power as used in corn packing. Saccharin is, how- 
ever, much sweeter, although to many the taste is objectionable. 

It has been reported that the use of saccharin in any food product has 
been prohibited by law in Germany on the ground that it is injurious to 
health. In this country, however, it is not regarded as an adulterant, as 
sufficient evidence of any injurious nature is lacking, and its use in can- 
ning will doubtless remain a matter of individual taste among packers. 

From what has been said regarding the effect of temperature on the 
development of bacteria, I think you can readily see why it is that some 
seasons are far worse for packers than others, and why some localities may 
suffer more severely than others even if they are not far distant. Thus, 
in a very hot summer, like last season, Maine would have a decided ad- 
vantage over New York and the Central States, because of its more north- 
ern latitude, and consequently cooler climate. In a similar manner a wet 
or a dry season probably exerts an influence on the development of germs 
in nature, but as data on these points are necessarily hard to obtain we 
can do no more than call attention to them. 

In this paper I have tried to express briefly, and I hope in a clear and 
straightforward way, what we regard as some of the important facts 
from the point of view of the canner. I hope I have shown the necessity 
for scrupulous care in every step of the whole canning process. In view 
of the many sources from which trouble may arise I believe the best re- 
sults will not be obtained until some measures are taken to obtain ac- 
curate scientific information along these lines. I can see no reason why 
the knowledge of the fundamental principles should not be sought just 
as eagerly in the preservation of food as in any other branch of manu- 
facturing. Surely none can be of greater importance to the public wel- 
fare. It is very easy to talk learnedly and at length about science in the 
abstract, but unless one can show just how this science has a practical 
bearing on the problems that are daily encountered in the industrial world, 
such talk is vain and may be wrongly construed. 

74 



The chair next introduced Mr. W. Lyman Underwood, who spoke on the 
subject : 

THE CAUSE AND i 'RE VENT ION OF SOUR CORN. 

Last year when I had the pleasure of addressing you at the Buffalo 
Convention I told how, in order to discover the cause of a mysterious loss 
which we were experiencing with one of our products, I became interested 
in the study of bacteriology as applied to our business — the canning of fish 
and meat. 

This question being solved and a remedy for the deterioration having 
been applied with success, I naturally became interested in some of the 
fermentations occurring in other branches of the industry. Sour corn, 
being the most prominent, about two years ago, with Mr. Prescott, I be- 
gan an investigation of this subject and we have been working on it ever 
since. 

As there are many packers present who were not at liuffalo last year, 
we have thought it best to make our papers somewhat in the nature of a 
review, although there are many new facts which are brought to your 
attention. At the conclusion of our article, which was presented to you 
at that time, we summed up our work as follows: 

1. That sour corn ap])ears to be always the result of bacterial action 
and due to imjitrfect sterilization. 

2. Tliat in case of insufficient processing souring does not always re- 
sult unless the cans are subjected to conditions favorable to the growth of 
the bacteria within. 

3. That some of the bacteria which produce sour corn are found on 
the kernels and beneath the husks of the corn as it comes from the field. 

4. That these bacteria found on the ears of corn corresi)ond in all 
respects to those originally found by us in cans of sour corn. 

5. That swelling may be caused by bacteria other than those which 
produce sour corn, but it is also a natural conse(|uence and a further de- 
velopment of this process of souring, provided the cans be subjected to a 
favorable temperature. 

6. That so far as we have been able to discover, the organisms pres- 
ent in sour corn are capable of producing serious commercial damage 
and an unpleasant taste but are otherwise harmless. 

7. That a vacuum is not necessary for the preservation of canned food, 
but is a valuable factor in the detection of unsound cans. 

8. That the use of bleaches or any antiseptic material is not to be 
recommended and is unnecessary if jiroper methods of sterilization be 
employed. 

9. That the utmost cleanliness at every step is absolutely essential. 

10. 'I'bat inlrrniittent sterilization is not practical on a commercial 
scale. 

75 



11. That the open water bath is insufficient as a means of steriHza- 
tion. 

12. That, with the present methods of retorting, it takes at least fifty- 
five minutes for the temperature which is indicated on the outside ther- 
mometer (say 250 degrees) to be registered at the center of a two pound 
can of corn previously heated in a cooker to 189 to 190 degrees F. 

13. That heating for ten minutes with a temperature of 250 degrees F. 
through the whole contents of such a can of sweet corn appears to be suffi- 
cient to produce perfect sterilization. 

Another year's experience has more than convinced us of the correct- 
ness of these assertions. 

In treating this subject we assume that the corn is in a perfectly sweet 
condition when it goes into the retorts in the can, and in our experience 
at many factories, we have always found this to be the case. Two facts 
prove the correctness of our assumption. First, we have found living 
bacteria present in cans of sour corn, thus proving that the sterilization 
was insufficient. They have been found repeatedly and with corn derived 
from many factories in widely separated localities. Second, in a large 
number of cases, especially in its first stages, souring may be found only 
at the centre of the can. When sampling a pack of corn where trouble 
is suspected this fact is often noticed. The corn may be sweet at the top 
of the can, but on taking a sample from the centre, souring will be found. 
Should these cans stand at a favorable temperature for some time the 
infection will become general throughout the whole contents. This proves 
that the heat sufficient for complete sterilization has not penetrated to the 
central portion on account of the low conducting power of green corn. 
It is, of course, possible that corn may become sour before going into the 
cans or before it reaches the retort, but it would be only uncler conditions 
of gross carelessness that it could occur in practice. If the corn had been 
sour before it was processed, this condition would not have been af first 
confined to the centre of the cans, but would have been equally distributed 
in all parts, and no amount of sterilization or processing could sweeten it 
again. 

As has already been stated warmth is particularly favorable for the 
growth of bacteria. The organisms which infest sour corn develop most 
rapidly in a temperature at or about blood heat. Upon this property of 
the bacteria depends the great and elaborate system of cold storage. A 
low temperature is not necessarily fatal to bacteria, but it prevents their 
growth and so arrests fermentations brought about by them. 

As a striking illustration of this principle we may cite the following 
facts : A Maine packer made two shipments of corn from the same day's 
packing, one to Bangor, Maine, and one to St. Louis, Mo., while a third 
portion of the same lot remained in his storehouse. In the following 
summer he received notice that the corn which had been sent to St. Louis 
had turned sour, while no complaint was received from Bangor. On ex- 
amining the lot remaining in the storehouse no trace of sour corn could 
be discovered. These results are absolutely to be relied upon as this par- 

76 



ticular day's pack was under suspicion and had been set aside and all ship- 
ments from it carefully recorded. 

In seeking the sources from which the bacteria causing this trouble 
might have come we examined ears of fresh green corn and upon the 
kernels and beneath the husks we have found bacteria which correspond 
in all respects to those previously obtained from cans of sour corn. 

There are many bacteria which can produce sour corn but we regard 
these as the particular ones most likely to give rise to the trouble. 

After the Buffalo Convention last year the statement was made that it 
would not be possible to isolate bacteria from cans of corn on account 
of the many thousand germs which were floating about in the air, since 
these germs were bound to get upon anything taken from the cans. This 
being the case it was said we would not be sure that any bacteria had come 
from the corn. In fact, the germs which were found must have come from 
the air and not out of the cans at all. 

We will tell you how we obtained these germs and you may use your 
own judgment as to whether or not we are right in our conclusions. 
Imagine a glass case some two and a half feet square with a door on one 
side which opens by sliding upwards. First the dust was entirely removed 
from the inside by washing with a cloth wet with a strong solution of 
corrosive sublimate. The cans to be tested were washed with the same 
solution, then placed inside the case, together with a Bunsen burner and 
an awl which were also sterilized. Now washing the hands with corro- 
sive sublimate and lighting the Bunsen burner, we are ready to begin. 
The door of the case is raised sufficiently to allow the admission of our 
hands. The awl is heated red hot and the can to be punctured is held over 
the flame and the hot awl is pushed through the tin. Should there be 
any vacuum in the can the flame, which must be germ free, will be drawn 
in, but no living germs can go with it, even if there should be any inside 
the case. Now with the platinum needle brought through this small hole 
and placed in the tubes of sterile culture media. If the can contained 
bacteria some of them would probably be taken out with the material on 
the needle and they would then continue to grow in the culture tubes, from 
which, by the usual methods, pure cultures could be obtained. No bac- 
teria were found in sound or good cans of corn when treated in this same 
way. 

There may be two varieties of sour corn distinguished as "flat sours" 
and those which show springy ends or "swells." ^^'c regard the latter as a 
further development of the former, which has been brought about by 
favorable conditions of temperature. However, we do not wish to give 
the impression that sour corn will always swell. As has already been said 
by Mr. Prescott, there mav be a fermentation in which onlv acid and almost 
no gas is produced. If, however, the temperature be higli enough there 
is generallv a smaller or larger amount of gas evolved. This fact is made 
use of in the tests for sour corn which we gave you in our paper last year. 

The fermentations arising in sour corn are similar in their cause and 
results to those occurring when milk sours. In each case we have an 

77 



undesirable product, yet we cannot regard it as essentially dangerous to 
health. Many people even like sour milk as buttermilk, and in some 
countries it is used as a part of the daily diet. So far as we have been 
able to ascertain none of the germs which we have found are disease- 
producing. 

As we told you in our paper last year the. vacuum is not essential for 
the preservation of canned goods, but is necessary in a way as an acid in 
inspection for the detection of unsound cans. It may seem needless to 
dwell upon this statement, yet so firmly has this mistaken notion that a 
vacuum is necessary become rooted in the public mind that even at the 
present time many people regard it as truth. It is well known to bac- 
teriologists that many germs can live and develop in a vacuum, the pres- 
ence of air actually preventing their growth. We can readily show by 
experiment that a vacuum is not essential for the preservation of corn and 
other canned foods. It is not the air which is harmful but the germs 
which may be contained in it, as we can easily prove by sealing a package 
with some substance, which, while freely admitting air, acts as a filter, 
thereby preventing the entrance of bacteria. 

(Mr. Underwood here showed flasks the openings of which were sealed 
with plugs of cotton. In them were shell fish, which though they had been 
processed over two years, were in an excellent state of preservation.) 

During the past two years the demand for very white corn has de- 
creased somewhat, for many dealers are already looking with suspicion 
upon it. The following incident will serve as a practical illustration of 
this statement : While in one of our large wholesale grocery houses quite 
recently, my attention was called to some corn which I knew had been pro- 
cessed according to our suggestions. I asked how this brand was selling 
and was told that it had the best sale of any line of canned goods in that 
house. They had heard nothing but praise of it though it was consid- 
erably darker in color than the corn which had been put out by the same 
packer three years ago. 

Here was an article containing no bleacher and thoroughly processed, 
thus insured against souring, which had an excellent sale at a high price, 
giving satisfaction to packer, dealer and consumer, because of its superior 
natural flavor. 

Our attention has been called to a circular issued by a well known 
canned goods manufacturer which also has a bearing on this subject. We 
quote an extract from it : 

"Our corn contains the natural cooked color and flavor due to complete 
sterilization and absolutely healthful ingredients, and we hope our patrons 
and consumers will aid us in destroying the market for white bleached 
or underdone canned corn ; that all suspicion of a deleterious foreign 
substance may be removed." 

We have here two views of this subject, that of the producer and that 
of the consumer, both in close accord, and were they accepted by all it is 
our opinion that sour corn would soon be a thing of the past. It is the 
fear that his product will be made unsalable that deters the packer from 

78 



processing- his curii to the extent re(|uired for complete steriHzation. Heat 
and heat alone should be the agency employed as a preservative for all 
canned food and the use of antiseptics, whether for bleaching or for any 
other purpose, should be condemned. 

Too much attention cannot be paid to the question of cleanliness since 
it reduces the danger of infection. Dust and dirt are the vehicles by which 
bacteria are often carried, and it is essential that such conditions siiould 
not exist. The liberal use of water and steam will do much to remove 
the chances of trouble from these causes. A frequent source of infec- 
tion and danger is found in the piles of corn cobs which are sometimes 
allowed to accumulate near the factory. Here fermentation sets in and 
in a short time multitudes of bacteria may be produced, which, upon 
drying, are easily carried by currents of air into tlic buildings. It is also 
important that the utmost despatch be exercised in handling the corn be- 
fore it reaches the process room, that the lialiility of infection mav be 
reduced to a minimum. 

There are three methods of sterilization by heat which may be applied : 

1. By steam under ])ressure in retorts. 

2. By continuous boiling as in an open water bath. 

3. By intermittent or discontinuous boiling. 

As the last method is much in use in laboratories for sterilization of 
small amounts of materials, and is sometimes suggested as being practical 
on a larger scale, we wish to outline the principle and the process involved. 
Mr. Prescott has already told you that bacteria, when in the spore state, 
are very resistant to heat and that they do not always remain in this state 
of development. This fact is taken advantage of in the process of inter- 
mittent sterilization. Assume that a substance to be processed contains 
numerous bacteria, both in the spore state and in the vegetating condi- 
tion. The substance is heated for a short time, perhaps thirty to sixty 
minutes, at a boiling temperature, 212° F. In the first cooking all vege- 
tative organisms are killed, while the spores remain unharmed. The 
goods are now set away until the next day when the process is repeated. 
In the meantime some of the spores will have developed into vegetative 
forms, owing to the favorable food conditions. These are destroyed by 
the second heating. After the second heating the substance is again set 
aside for another day to allow the development of the remaining spores, 
and is then given a third and final heating, which, according to the old 
ideas, should produce complete sterilization. It will readily be seen that 
the use of this method involves the handling of goods a number of times, 
and moreover, requires a much greater outlay in plant and labor. Aside 
from the impracticabilitty of adopting this method on a large scale, there 
are a number of other serious objections to its use, particularly with a sub- 
stance like corn, which, as we shall presently show, is a poor conductor 
of heat. It may be suflftcient to say at this time that in order to make the 
process at all efficient each heating would necessitate more than an houf's 
time. We have proved that it takes an hour and forty-five minutes for 

79 



a temperature of 212° F. to reach the centre of a can of corn. More- 
over, there can be no absolute certainty that all spores of bacteria would 
develop into vegetative forms by the time of the third heating, and unless 
this were so the whole process would fail of its end. 

In preserving nearly all the more putrescible foods, the open water 
bath has been almost entirely given up as an agency of sterilization. 
Practical experience has demonstrated that it is unreliable. Within the 
past year we have been in communication with a packer who had up to 
1898 always processed his corn at boiling temperature. He frankly told 
us that they had had more or less sour corn each year and were very much 
puzzled by it. When one bears in mind that the spores of bacteria will 
often withstand eight to ten hours of boiling, the reason for this loss is 
not difficult to see ; and it also offers a striking example of the insuffi- 
ciency of this method. On the other hand, the use of steam under pres- 
sure, by which temperatures high above the boiling point of water may 
be reached, undoubtedly offers the best means of processing corn. So 
far as we can ascertain this is a safe and sure method if properly controlled'. 
To obtain satisfactory results, however, it is necessary to know definitely 
the time which is required for the heat to penetrate to all parts of the 
can at whatever temperature it is the custom of the packer to give. 

In order to determine more thoroughly the relations of time and tem- 
perature which should govern the sterilization or processing of corn, we 
have carried on during the past season a prolonged investigation of this 
subject involving over 400 tests, made both in wet and dry retorts, and 
in a number of different localities. The corn which was used in these ex- 
periments was of a consistency of the standard New York quality which 
had been run through the cooker at about 185° F. This corn was pro- 
cessed at the following temperatures : 235, 240, 245 and 250° F. and at 
each of these temperatures different periods of 40, 45, 50, 55, 60, 65, 70 and 
75 minutes were given. The method of procedure was as follows : In 
the centre of each can was placed a thermometer which registered maxi- 
mum temperature reached. Tlie cans were distributed in different portions 
of the retort and each test was repeated several times in order to get a 
larger number of readings from which to obtain our average results and 
to diminish any liability of error. The time was first taken when the out- 
side thermometer showed the temperature at which the run was to be 
made, and at the end of the period of heating the cans were immediately 
cooled in cold water. The thermometer readings were then taken and the 
averages ascertained. As these may be of interest to you, we will give 
them in detail : 
Minutes. 235° 240° 245° 250° 



40 


226 


233 


234 


^}>7 


45 


227.5 


234-5 


236.5 


240.5 


50 


229 


236 


239 


244 


55 


231 


237-4 


241 


247-5 


60 


233 


239 


243 


250 



so 



Minutes. 235° 240° 245° 250° 

65 235 240 245 250 

70 235 240 245 250 

75 235 240 245 250 

For comparison \vc have tabulated these results in the manner shown 
above. The figures in the first column indicate the duration of heating 
in minutes. At the head of the other columns are given the temperatures 
at which the tests were made while the figures below give the temperatures 
obtained for the different periods of time. In this way we can easily show 
the length of time required for heat to penetrate to the centre of the cans 
at any given temperature. It will also be noticed that the higher the 
temperature of the run the more quickly the heat reaches the centre of the 
can. 

The results of these tests should not be applied universally, as the con- 
ditions may vary somewhat between individual packers or different locali- 
ties. The conditions here referred to apply particularly to the consistency 
of the contents of the can, whether it be a very moist or a very dry pack. 
The amount of starch in the corn would influence the temperature some- 
what ; that which contained the more starch would take the longer to heat 
as would also be the case with corn which had but little moisture added 
as brine or syrup. 

Our opinion has often been asked as to the advantages of the wet over 
the dry retort or vice versa, and we will give the facts as far as we have 
been able to obtain them from this line of investigation. 

We in New England hardly know what a wet retort is and I myself 
have never seen one in use there, about all the processing being done with 
dry steam. It is a common thing to hear a packer say, 'Tf water should 
stand in our retort it would spoil the cook and the goods would not keep." 
In a way he may be right, though the trouble would not be due directly to 
the presence of water. In running a dry retort it is very important to 
have a free exhaust to insure perfect circulation of steam and an even 
heat. Without it the circulation would be very imperfect and the tem- 
perature in some parts of the kettles might be lower than that indicated 
by the outside thermometer. With such conditions we shall find water in 
the retorts which has condensed from the steam and its presence is a direct 
indication that the heat might not have been equal in all parts of the retort. 
It is also important that a good exhaust he given in running a water 
retort as the rules of circulation and distribution of heat are similar in 
both cases. Our experiments with both methods have been made with 
retorts which were run correctly but in the usual way. Under these con- 
ditions we have found no advantage to be gained by the use of one kind 
rather than the other, imlcss it be a question of convenience, or work in 
handling. In both cases an ecjual time is required for a given tempera- 
ture to be registered evenly in all portions of the retort, and no prefer- 
ence can be shown. The figures which wc have given relating to heat and 

81 



time were derived from both methods and can be apphed to one or the 
other. 

As before stated, these tests cover all portions of the retort and from 
them we gain some knowledge of what has been considered rather a per- 
plexing question, namely : Does it take longer for a given temperature 
to reach the central cans in a full retort than it does those at the top, bot- 
tom or sides, and is the heat at all times equally distributed? Our tests 
have shown that at periods between 30 and 60 minutes at temperatures 
from 235 to 250° F. the central cans are heated as quickly as any other, 
and the heat is evenly distributed throughout the retort. A very slight 
difference was noticed in short runs between the central and outside cans, 
but it was so small as to be of no practical disadvantage. 

We have often heard it stated that the wet retort gives a better quality 
of "cook" than does the other method. It is claimed by many that the dry 
retort has a tendency to over-cook. This certainly has never been proved 
to our satisfaction, and we think a little deliberation on the subject will 
show that it is not a fact. Two kettles of corn were processed for 65 min- 
ues at 250° F., one was filled with water and the other was run with dry 
steam. They were so timed that the cans from each were withdrawn and 
cooled together. After cooling six cans were opened from each lot and 
no difference could be noticed in texture or in color. We have made sim- 
ilar tests with other goods besides corn, and with the corresponding results. 
At first thought it would seem that the water retort must give a different 
quality of cooking, but it must be remembered that in each case the tem- 
perature was exactly the same and the cans being hermetically sealed the 
contents could not be affected by the water. The difference between pro- 
cessing with dry and wet retorts should not be confounded with ordinary 
roasting and boiling. 

We may roast a piece of beef or we may boil it. Here there is a vast 
difference in the condition or texture of the meat so treated. But there is 
also a great diff'erence between the methods of cooking. One is a very 
drv heat at a very high temperature ; the other a moist heat at a compara- 
tively low temperature. In both cases this heat comes in direct contact 
with the food, in the first instance driving the moisture from, and in the 
second adding moisture to the meat ; while in the retorting of canned food, 
moisture can'be neither taken from nor added to the substance in the cans. 

Every packer should know to his own satisfaction just how long it takes 
the temperature at which he is processing to reach the centre of the cans 
of corn which he himself is packing. Never mind what your neighbor is 
doing. He may be packing corn that never sours and is giving it but 55 
minutes at a temperature of 245° F. while your corn is sour which was 
given 65 minutes, 10 minutes more than he gave, at the same or perhaps 
even a higher temperature. But he forgot to tell you, or perhaps he did 
not know" that he was adding a much larger quantity of water than you 
were. To show what an important factor the amount of water is, I may 
state, that a registering thermometer, placed in a can of cold water, will 
show the same degree of heat that is indicated on the outside retort 

82 



tliermomctcr. say 240° F., in six minuUs, wliile it takes about 65 minutes 
for a rc.2:istering tliermomctcr in a can of liot corn of standard (lualitv to 
show the same temperature. 

Some packer may tell you that the limit of heat is reached in his jxick of 
corn in 30 minutes. He knows this is a fact because he has used register- 
ing thermometers, but should you investigate his methods, you would likely 
find that his thermometers were not placed in the ceiUre of the cans. They 
ma\- have been ])laced in the centre of the cans. l)ni no precautions taken 
to keep them there, so that the heat recorded was fmm ihc side of the can 
not from the most important point, the centre. 

Experiments are of little use and may be often misleading unless they 
are carried out with a thorough knowledge of the principles involved. 
Sooner or later the rule of thumb methods must give way to the applica- 
tion of scientific laws, and there is no industry in which their application 
has larger scope than in that in which we are all engaged, the i)reservation 
or canniui"" of food. 



There were a great many (piestions asked of the ])rofessors and thev 
replied to all with the best of their knowledge and ability. Anmng some 
of the (|uestions ])ropounde(l to them the following are taken : 

.Mr. IloKkn of Chicago asked whether or not the bacteria existed on 
the inside of the kernel of corn or always on the surface; and how about 
tomatoes for instance. 

Answer — h>om what we found llu'\ are on the outside. Relative to 
the <|uestion of the li(|uid or brine, the professors statetl that it would 
take 40 gals, of water, 16 lbs. of cane sugar, 8 lbs. of salt; or according to 
desire put in a little more sugar. That is about the proportions to make 
brine or the liquid. Which is the best climate to keep canned goods fresh? 
Dry, of course. The professors stated that in order to keep the goods 
healthy and fresh, cleanliness was necessary around the factory, for instance 
keep the corn cobs away, as if thev are on a pile around the factor\- they 
will ferment and the unhealthy germ will be prevalent in the factory before 
and after the goods are placed in the can. In regard to tlie climate — I 
know of a case where a packer shipped corn to Bangor. Ale., and from the 
same pack also shipped to St. Louis. The goods shipped to St. Louis they 
received complaints on. but none from Bangor. These goods were taken 
from a stock of goods where there was liability of bacterial action. 

Mr. Simms — Are the bacteria which create what is known as cornstalk 
disease of the same class as those which are in the can ? I ask this for the 
reason tliat I received quite a heavy loss through tiie death of cattle who 
had eaten corn stalks which were supposed to have been affected by this 
disease ? 

Answer — I do not think so. as I have eaten sour corn in the course of 
mv experience and am still somewhat alive, although I may be tougher than 
vour steers. 

83 



Mr. Polk — Does the quickness or the slowness in the cooling of the 
goods after coming from the process have any material^ effect on the color 
of the corn ? 

Answer — If it is thoroughly processed to cool at once is of advantage. 

Mr. Ott — What temperature is the most advantageous and safest in 
processing corn ? 250 appears to be sufficient to produce perfect sterilizing 
— 65 minutes. 



84 



CHAPTER IV. 

Ai the annual conxcntion of the L'anucTs" associations held at Detroit 
I'ebruary, 1900, Messrs. TrL'scott and L'ndcrwood were not present, but 
a characteristic letter from them to President R. Tvnes Smith, of the At- 
lantic States Packers' Association, was read. and. heinsj: pertinent in every 
w av. it has been deemed worthy a place in this work : 

Uostmi, Mass.. l'"eliniary 7. K^oo. 
Mr. R. I'yucs Siiiilli. Baltimore, Md. 

Dear ^ir: Vot the past two years we have derived much pleasure from 
attending the conventiiMis of the packers' associations held at Ihift'alo and 
Detroit, respectively, and we regret exceedingly that it will he imi)ossible 
for us to be with you again this year. 

At Detroit last year we listened with a great deal of interest to the ex- 
])erience of packers who had availed themselves of our suggestions, and 
conducted their i)rocesscs in accordance with the methods outlined l)y us 
at lUitifalo in i8<;S. It is a source of tuuch satisfaction to find that the 
canners are. in general, manifesting so nuich interest in this subject, partic- 
ularly so when it is remembered how reluctant many were at first to enter- 
tain any belief that bacteria could be at all responsible for many of the 
losses incurred in the industry. So firmly diil the jniblic mind connect bac- 
teria with human disease only that it was natural. perhai)s, that there 
should be some hesitation in accepting any theories which had to do with 
germs, and it is not to be wondered at that even now there are some who 
are still skeptical, or who do not fully understand the true relations which 
micro-organisius bear to spoiling and deterioration. 

In looking over a recent issue of a pa])er j)ublished in the interests of 
the canned goods trade our attention was attracted to a statement in con- 
nection with the new form of cotUract for the sale of canned gcxxls which 
has been drawn uj) by the Xew York Wholesale (irocers' Association. It 
is relative to "latent defects" which sometimes appear in canned goods, and 
it i^ractically stated that all canned foods not only are liable to develoj) 
swells if they are much moved about or disturbed, but will invariabh do 
so, the trouble being jjroduccd by sotne "latent power" within the can. 

Without going into any discussion of the i)ro])riety of this clause as ap- 
l^lied to the contract, we shoulil like to consider this statement somewhat 

85 



in detail for it furnishes food for a good deal of thought. If it is true, 
it is a virtual acknowledgment that no canned goods are perfectly sterilized 
or processed. 

It is known by actual experience that this is not the case, and any packer 
who can not guarantee his goods unless they can stand quietly on the 
shelves should go out of business. To show at once the absurdity and fal- 
lacv of such a statement, it need only be cited that there are annually thou- 
sands of cases of canned goods transported on long sea voyages, which 
must of necessity receive severe and continued agitation, and that they do 
not always necessarily develop swells goes without saying. The disturb- 
ance and shaking up received in this way are far greater than could ever 
be obtained by any moving about in a grocery store, and one would expect 
the "latent power," if any existed, to be developed in a correspondingly 
greater degree. The facts, however, do not bear out this theory. 

It is true that unless the canner knows absolutely tbat his process is 
right he is liable to have goods with latent defects, which are due to the 
presence of bacteria or other spores which have not been killed, and whose 
development may oftentimes be hastened by agitation and may result in 
swells. It can not be denied that under these conditions a latent power 
exists in the cans, which, if given the right conditions, will manifest itself 
in swells or other deteriorations, as we have shown in previous papers. 

However, we not onlv question, but absolutely deny that swells may 
invariably be produced by shaking the cans, and any packer who admits 
that the statement referred to is true in his case at the same time acknovv^l- 
edges that his goods are not thoroughly processed, or at least that he does 
not know whether they are or not. 

In other words, if a packer is sure that his product is put upon the 
market in a thoroughly prepared condition, there seems to be no reason for 
him to fear any swelling of his goods due to latent defects. It makes no 
difference whether the substance be corn or peas or any other food product, 
tlie principle underlying the preservation for indefinite periods is steriliza- 
tion, and thoroughly sterilized foods should keep for years, as well as for 
months or weeks, so long as no mechanical injury is done to the cans con- 
taining them whereby bacteria could come in contact with the contents of 
the package. 

There is one contingency which may arise which might seemingly dis- 
prove this statement. Sometimes conditions may exist where a verv small 
percentage of loss is noticed in goods that have been thoroughlv and suf- 
ficiently processed, this loss not occurring until a considerable length of 
time had elapsed after the goods had been put upon the market. Anyone 
who is well versed in cause and effect can readily account for this situation. 
In overhauling and inspecting a stack of canned goods previous to labeling 
and shipment there are often a few leaks which can not be detected, owing 
to the fact that the minute hole had been mechanically closed during the 
process of cooking by some particle of the substance within in such a way 
as to seal the opening effectually for the time being, therebv causing the 

86 



can to have a vacuum, and !.',i\inj^' it all tlir appearances of a perfect can. 
By violent shakini^- at sonie later time such a particle may be dislodj^^ed, 
and the vacuum will be sufficient tn draw in some oerms with the air, and 
as a result of the bacterial action swellins^" would most proliably ensue, 
though this could not, of course, lie regarded as due to any latent jiower 
originally existing within the can. 

Each year, as the knowledge of bacteriology advances, its application 
to the food industries becomes wider and of more importance. It has been 
shown that it is not the exclusion of air which causes canned goods to 
keep, but rather the exclusion of living germs, ^'ear by year canners will 
find increasing necessity for the application of scientific principles in their 
business. As competition grows the need of accurate processes will become 
more .ind more ap])arent, and these ]:)rocesses will be worked out ihrough 
the medium of scientific investigation. 

A subject wkiich can not be too strongly brought before the minds of 
practical men engaged in canning industries is the necessit>- of watchfulness 
as to the sanitary condition of the products which they \)u{ upon the market, 
and the more the public is made aware of the fact that the i)usiness is con- 
ducted upon sound and scientific principles the greater will be the demand 
for this class of foods. 

Trusting that the convention of 1900 will be very successful, we beg to 
remain. ver\- trulv \ours, 

SAMUEL C. PRESCOTT, 
* WM. LYMAN UNDERWOOD. 



87 



CHAPTER V. 

At Rochester in I'\l)niar\. ii;()i, during; ilie sessions of the various can- 
ners" associations ])resenl. Mr. W. Lyman Lnderw^Hvl read a ])aiKT covering 
the various bacteria t'nund in canned croods. while rnifessor I'rescott ,qave 
his attuitinn tn the subject of "Sour Peas." Mr. rnder\v<ii)d sjidke first on 

ll.Xnd'.KIA !.\ e".\\.\i:i) l-'( )()!). 

About five years ago Mr. I'rescott and 1 pubhshed the results of some 
of our investigations, to find the cause of deterioration and loss that was 
being met with in certain canned foods, particularly fish products. 

As the changes which such substances underwent were similar to fer- 
mentations or putrefactions, we came to the conclusion that, owing to in- 
sufficient processing or sterilization these peculiar conditions were caused 
bv germs. In cans that had spoiled we found living bacteria, which, on 
being inoculated into good cans. ]M-oduced the same striking characteristics 
that we had noticed in the original cans. We also found that a temperature 
of 212 degrees Fahrenheit, or a boiling heat, was insufificient to process these 
foods thoroughly, when certain germs were present. If these organisms 
were present it seemed to make no difiference whether the goods were boiled 
for three lunirs or for eight hours. Over 90 ix'r cent, of cans so treated 
spoiled when subjected to a tropical heat. 

These experiments were carried on at the biological laboratory of the 
Massachusetts Institute of Technology and the report upon them was prob- 
ably the first information that had been published upon work of this kind. 

At that time the knowledge that the general public entertained in regard 
to bacteria was rather vague. ]\Iost people associated them only with 
disease. I well remember, when first we ventured to speak with some of 
the packers, on this subject, how we w-ere met with a look of suspicion and 
in some cases were told that if we dared to connect germs with canned godds 
(a topic which was never to be discussed in public) it would ruin the busi- 
ness. So firmly was this idea rooted in the minds of many that, in our 
early work, we had to be extremely guarded about whatever w-e said uj^on 
the subject, lest we should not only offend jK'ople. but reallv so frighten them 
that they would not ever wish to eat any more canned food. 

89 



Our first paper was read in Boston, before the Society of Arts, an asso- 
ciation for the advancement of science. A year after our pubhcation the 
Canadian government issued the result of an investigation, which had been 
carried on under their direction, to ascertain the cause of "black lobster," 
as it was known to the trade, a trouble which seemed likely to demoralize 
the whole lobster-packing industry. 

This deterioration was seemingly a very mysterious one, for the lobster 
meats turned dark without swelling the cans and, in some cases, the entire 
contents were changed into a black, foul-smelling liquid, without any indi- 
cation that anything was wrong. 

This investigation of the Canadian government confirmed the conclu- 
sion which we had drawn, namely, that the trouble was brought about 
through the action of certain bacteria that had the power to resist the boil- 
ing heat as ordinarily applied. As a method of prevention they recom- 
mended that canned lobsters be processed as follows : First, boil for one 
hour ; then cool at once and keep cool from twelve to fifteen hours. Second, 
boil again for fifty minutes ; cool and keep cool, as before, from twelve to 
fifteen hours. Third, apply same heat again. This time for forty minutes ; 
cool at once. In warm weather give a fourth boiling of thirty minutes, 
after keeping goods cool for twelve hours. 

By this system it will be seen that in warm weather four days would be 
occupied in finishing any one day's pack of raw material, and starting at 
the beginning of the season, after the third day. one would have to process 
daily the w-ork of three preceding days. 

While this method (which is known as intermittent or fractional sterili- 
zation) may be practical for the laboratory or in domestic and household 
work, it cannot be carried out on a large commercial scale, where thousands 
of packages have to be handled and processed daily. 

The Canadian government report further states that if a temperature 
over 212 degrees Fahrenheit, the boiling point, were adopted it would ne- 
cessitate the use of retorts, which few factories possess and which are be- 
yond the reach of many worthy men. Later, it claims that the methods of 
using the retorts are faulty "because the temperature of 248 degrees Fahren- 
heit, which is commonly used, is too high for any tissue intended for food." 
That this statement is at variance with actual facts goes without saying, 
for nearly all our food, which is baked at home in an oven, is subjected to a 
much greater heat than that above mentioned. 

Flundreds of retorts are being used to-day at temperatures ranging from 
240 to 250 degrees Fahrenheit, and notwithstanding what the Canadian 
government has said we have found it possible to so sterilize canned lobster 
in retorts that it will keep perfectly sweet and hold its delicate flavor and 
color without danger of spoiling. 

For a long time it has been known that canned lobster from one district 
was more apt to turn black than that from another. For instance, shell fish 
from the southerly shores of Prince Edward's Island are more liable to 

90 



develop this trouble when packed, than those from the Xova Scotia or New- 
foundland coasts. There now seems to he a very detinitc ex])lanation of 
this. The waters about Prince Edward's Island are shoal and the bot- 
toms are, for the most part, muddy. In this mud (which is so rich that it 
is often used for fertilizinfi^ the land ) bacteria abound, and it is easy to see 
that fish which have been feeding off such shores would naturally take in 
with their food many of these germs. INIoreover, it is a well recognized fact 
that this blackening of canned lobster generally starts first in the meat of 
the tail, along the intestinal tract, where it would be expected to be found 
if the trouble were due to such germs. 

( )n the other hand, the shores of Xova Scotia and Xewfoimdland are 
bold and rocky and the water is colder and deeper. Such conditions are 
unfavorable for the growth of bacteria, consequently the lobsters which 
frequent these territories are not liable to spoil, after being camied, because 
their food does not, to any appreciable extent, contain any of these germs. 

In packing clams and oysters a peculiar kind of spoiling has sometimes 
been met with, which is similar in all respects to that occurring in lobsters. 
In the mud Hats, where the clams are dug, we have fotmd bacteria that seem 
identical with those found in the spoiled cans. As these microbes are 
|)revalent in such localities it is very important that any hsh which have 
frequented or have fed on such grounds and are to be used for canning, 
should be thoroughly sterilized or trouble may ensue. 

As there are certain bacteria which affect fish and meat products so, 
also, there are others which may aft'lict the packers of fruit and vegetables, 
through their action on these foods. Sweet corn offers a striking example 
of this. You all know that thousands of dollars have been lost in the past 
through corn souring in the cans. Sour corn has probably been the greatest 
source of financial loss in the long list of troubles caused by these minute 
foes, and has been a veritable curse to the industry. 

The result of our investigation in this direction we gave to you at Buf- 
falo three years ago, and we hope that it has been of benefit to those en- 
gaged in this business. So far as we have been able to learn, there have 
been no further losses among manufacturers who have carried out our sug- 
gestions and we hope that sour corn is a thing of the past with them. 

i'i:.\s Axi) oTHF.u \i:r,i:T.\iuj':s. 

There are, however, other vegetables which are subject to extraordi- 
nary changes. If not thoroughly processed as])aragus will sour as will also 
squash, pumpkin and peas. In all of these products we have found bacteria 
which are very resistant to heat and which to eliminate re(|uire special treat- 
ment in each case. I'erhaiis the most extensive trouble that is now menac- 
ing the business is to be found in canned peas, and Mr. Prescott will soon 
tell you something of our experiments in this direction. 

\\'e often hear it said that years ago there never used to be any myste- 
rious los.ses in the business, and we frequently asked why should there be 
more trouble now than then? W'e answer that formerlv there were, no 



doubt, as many, if not more, difficulties to be overcome than there are now, 
in proportion to the amount of business done. From a letter written by my 
grandfather in 1850 I quote the following: "The season, ending last year, 
has been a very strange one, and some of our hermetically sealed goods have 
spoiled, although they were put up with great care and of the -best quality, 
and we can only suspect that the whole atmosphere has been impregnated 
with cholera that acted upon animal matter as it did upon vegetable. Our 
process has been the same for a number of years, with the exception of a 
little more care in that process last year than heretofore, because we had 
known of others having the same trouble. We wish you to be very par- 
ticular and not suffer any of our hermetically sealed goods to go out of 
your hands until you have opened a few packages of each case." 

It would seem by this that the year of 1850 was a bad one for those in 
the canning business. Bacteria were prevalent ; but, in those days when 
there was no way of applying a sufficient heat for sterilization and it was 
not understood that a higher temperature was necessary, the packers prob- 
ably suffered more losses in proportion than at present. 

Why it is that some years are more disastrous in these respects than 
others is not definitely known, except in so far as climatic influences are 
concerned. During seasons of extreme heat and moisture the conditions 
are favorable for the growth of the micro-organism that causes these losses 
and at such times unusual care must be exercised to guard against them. 

In the case of germs that cause disease it is not understood why they 
should be more prevalent in some years than in others ; but that they are so 
is recognized and on such occasions every precaution must be exercised to 
retard their progress. I believe that it is for the interest of all packers 
to let the people know that their food is being prepared scientifically. For 
when this information becomes general then some of the prejudices against 
canned goods which are still deeply fixed in the minds of many will be 
removed. 

Few people realize to what an enormous extent this industry has already 
grown. Some idea may be had of its proportions when it is known that 
if all the cans of tomatoes which were packed in 1899 were placed end for 
end they would reach more than half way round the world, for they would 
form an unbroken line of 13,428 miles of cans, and this is only one of the 
many varieties of foods which are preserved. 

The science of bacteriology is advancing very fast and the importance of 
this study to the industrial world is becoming more and more evident each 
year. In Germany the government has appointed special commissions to 
work out some of the problems that perplex the preservers of food. 

In our country the people are rapidlv acciuainting themselves with the 
ways in which bacteria work for the good or ill of all, and we are no longer 
obliged to speak in whispers when we discuss the germs that affect the 
canned goods business. We have always had to contend with them and 
always shall have to, for that is what the preservation of food means — a 

92 



war against bacteria, and while formerly it was a fight in the dark and 
against an unknown foe, now, with the modern weapons of the twentieth 
century and the knowledge of micro-organisms which science has brought 
to us, the lines of attaclc have become more clearly marked, but the strug- 
gle must go on as unremittingly as ever. 

Mr. Chairman : I would like to ask Professor Underwood if he has 
done any further work on the subject of sour corn since the last paper was 
read. 

^[r. L'nderwood : Xo, we have not nor have we arrived at any different 
conclusions than we did at that time ; the times which we gave you and 
the heats which we thought necessary, we still think ap])ly to that brcUich 
of the industry, and we have not heard, as 1 said before, that anyone lias 
suffered any further loss who ran along the lines we suggested. If t'r.ere 
have been any we should like very much to know it. 

Chairman Ilulibard: 1 have the pleasure now of introducing to \<)u 
Professor Prescott. 

SOrPTXC OF l^KAS. 

Investigation of the souring of peas, by Prescott and l'nderwood. Read 
by S. C. Prescott : 

When we addressed the convention at Detroit in i8i/j we attemi)ted 
to give a clear and concise account of our work in which we proved the 
time necessary for bringing about sterilization in canned corn. Although 
more than three years have passed since this work was done, we have as 
\et to learn of a case in which the methods we were able to arrive at have 
proved unsatisfactory, if ajijilied properly. In descril)ing this work it was 
our purpose to show not only how best the ])ublic could be served in this 
matter, but. also, how best the canner could lie ensured against loss at the 
same time. 

\\'hile the subject for consideration, viz., the bacteric^logical investiga- 
tion of canned goods, has lost something of its original freshness owing 
to the fact that the ground has l)een gone over more or less thoroughly each 
year for the past three years, we are going to risk lioring you. and give you 
a brief account of some work, conducted on a rather large scale, made to 
determine the cause and if possible to suggest a remedy for sour peas. The 
general plan of the work was much like that emjiloyed in the earlier investi- 
gation of sour corn ; that is, we went to the factories in the packing season 
and studied the subject on the ground — packing ])eas under varving condi- 
tions, ])rocessing in various ways and luaking comparative cxju'riments at 
different localities and different factories. 

The cardinal points which we tried to ascertain were f(~)ur in number : 

1. Time necessary for sterilization. 

2. F.ffect of "sweating" liefore processing. 

3. Influence of age of peas on keeping qualities. 

4. Effect of locality. 

93 



It is probably unnecessary, yet may not be out of place to state that we 
were convinced at the outset that sour peas were due to a fermentation 
caused by bacteria, which might not have been killed in processing, or which 
had already produced the souring before processing had been given. In 
many instances the former proved to be the case, for by making bacteriologi- 
cal examination in the way which we described for sour corn we were able 
to isolate and cultivate the organisms which were responsible was proved 
by the introduction of the germs obtained into perfectly sound cans, and 
thereby producing the spoiled condition. In this way we could spoil peas 
at will. 

Being thus assured of our enemy, we proceeded to work out the four 
important points which I have already mentioned. 

I. Time Necessary for Sterilization. 

Sterilization is rendering free from bacterial life. The time necessary 
for sterilization may be defined as the shortest time in which goods may be 
processed with the result that they will keep indefinitely and all micro- 
organisms be destroyed. Experiment and experience both show that under 
certain conditions some peas will keep while others given the same treatment 
will not. Obviously, then, we can not regard this as proper sterilization, 
since unless all bacterial life is destroyed there still remains a grave danger 
of loss. On the other hand, if the most resistant germs are destroyed then 
we may be confident that the weaker ones will succumb. 

In determining the time necessary for complete sterilization, we com- 
menced with cans packed in the usual way, but which had been given a very 
short processing, and noted the efifect of gradually increasing the length 
of the heating up to a period somewhat longer than that actually given in 
practice. This was repeated several times with peas of various sizes and 
ages, as will be seen later. These cans were incubated for a period of several 
weeks, and finally were all examined chemically for aciditv, and were tested 
by taste. The chemical changes involved here may be two in number : first, 
and most marked, being the development of lactic acid and other acids by 
the action of bacteria upon the carbohydrates and, second, the formation of 
products having disagreeable taste and smell by the breaking down of the 
nitrogenous substances present in the peas. This result is also due to bac- 
terial action. 

Bacteriological examinations were also made to determine if germs were 
still present in the living state. Even in case the bacteriological examination 
gave negative results in the presence of strong acid, it does not show that 
bacteria have not been present and active. On the contrary, it shows that 
their activity has been great, but that the non-removal of their products 
has brought about a slow poisoning action which finally resulted in death. 
A few moments' consideration will show that in all living things such a rule 
is good. The substances which we throw off as a result of our life-processes 
may be poisonous in large amounts. 



94 



It was finiiid hy making- thermometer experiments tliat it required a 
little less than ten minutes for a temperature of 236 degrees l\ to penetrate 
to the center of the two pound cans. ( )f the cans that were run for fifteen 
minutes. 50 per cent, showed hacterial growth; of those nm twenty nnn- 
utes, 25 per cent, showed growth; wliile those which were run f^r thirt\-Hve 
minutes were nearly all found to he sterile. Xo cans which had been giyen 
forty minutes spoiled, eyen when subjected to most fayorable conditions in 
an incubator. The i)ercentage of spoiling in all our tests was much greater 
than would liaye been the case had the cans been allowed to stand at a nor- 
mal tem])(.Taturt', as in actual business practice. In all our tests the cans 
haye been subjected to a constant temperature of blood heat (i^S degrees 1'.) 
in an incubator, for oyer two months. 

It is interesting to note that in these tests we haye found that where 
spoiling occurs in peas j^rocessed for fifteen minutes or less at 236 degrees, 
in nearly eyery case the cans were swelled, while those which had been 
processed for more than fifteen minutes, and still showed bacterial gn^wth, 
were for the most part sour in taste and acid in reaction, but showing no in- 
dication of swelling. The reason for this is that the gas producing bacteria 
arc killed by the longer heating while other species, more resistant to heat 
but not able to produce gas, are not destroyed and later bring about the 
generation of the acid. 

When it was first found that only about ten minutes is necessar\ to 
bring the center of the cans up to 236 degrees F.. we thought that the 
time of sterilizing could be consi(kral)ly reduced, as in our preyious experi- 
ence with corn we had found that ten minutes, after the heat hatl penetrated 
to the center of the can, was sufficient for sterilization. But it must be 
borne in mind that the temperature at \yhich peas are processed is somewhat 
lower than that used in the packing of corn, and the time of heating neces- 
sary for sterilization must be much longer. Thus germs which reipiire 
ten minutes at 250 degrees V. to be killed may require twenty to twenty-fiye 
minutes at 235 degrees to produce sterilization. Our retort experiments on 
corn showed that at the end of forty minutes at 250 degrees a temperature 
of 236 degrees was reached at the center of the cans, so that corn which re- 
ceiyed sixty-tiye minutes was getting twenty-fiye minutes at or aboye 236 
degrees, which is practically what the peas are receiving when run thirty-fiye 
mimites at 236 degrees. Allowing ten minutes for the heat to penetrate to 
the center of the cans, they then got twenty-five minutes at this beat 
throughout. 

By referring to our table on the retorting of corn, it will be seen that, 
if processed at the same temjierature as peas, it would take eighty-five min- 
utes to produce the same relative effect, as it requires sixty-five minutes 
for this heat t<^ reach the center of. the cans of corn. 

95 



Szccatiiig. 

If peas are allowed to stand for several hours about the factory, and 
the conditions are favorable, sweating will result, and this we believe to be 
largely responsible for sour peas. 

We carried on a great many experiments along this line, and on opening 
the cans in every case we found sour peas. In this connection we brought 
out a striking fact ; that is, that after sweating for several hours or over night 
the peas which have already become acid or sour may be sterilized in a much 
shorter time than fresh ones. A large majority of cans which were given 
but twelve minutes showed no further growth, nor did they swell. All 
cans retorted for more than fifteen minutes were found to be sterile, although, 
of course, sour. These results are probably due to the combined action of 
two factors, the acid already developed together with the high heat, as hot 
acid solutions are more effective than hot water in killing bacteria. More- 
over, lactic acid is germicidal and by its long continued action would bring 
about the death even of those organisms which produced it. It is also 
probable that while sweating is taking place the germs multiply with great 
rapidity, being present on the surface of the peas not as spores but in the 
vegetative state, and so more easily destroyed. 

The peculiarity just mentioned was especially observed with young and 
tender peas, while, as would be expected, the older and tougher ones required 
longer cooking than the young ones. This influence of the age of the peas 
on the time required for processing has also been noted in peas packed 
"normally," that is in the ordinary way without previous sweating. The dif- 
ference, both in the case of peas which have undergone sweating and normal 
peas, appears to be due, in part at least, to the fact that in the yovmg peas 
the amount of sugar is greater, while starch is more abundant in the older 
ones, and this sugar is not only more readily fermentable, giving rise to 
larger amounts of acid in a given time, but its conducting power is also 
greater, and so allows the thorough cooking of the peas in a shorter time. 

Inoculation Experiments. 

After making the experiments just described in which peas had been al- 
lowed to undergo sweating, we next inoculated living germs into cans 
of fresh peas and subjected them at once to treatment in the retorts, with- 
out giving any spores which might be present a chance to germinate into 
vegetative forms. As would be expected, in the cans given short periods 
of heating, some spoiling took place, but all cans given the full period of 
thirty-five minutes at 236 degrees remained sterile, and subsequent cul- 
tures made from those cans proved them to be free from living germs. The 
germs used in these inoculations were of species originally found in sour 
peas, and hence desirable to use for this purpose on that account. 

Effect of Locality. 

We also experimented to "ascertain if there was any difference in the 
keeping qualities of peas frojn different localities, providing they had been 
given the same treatment. The localities selected for these comparative 

96 



tests were three in number and from eighty to one hundred and fifty miles 
apart. At two of the places certain differences of procedure from that 
employed at the third, where most of our work was done, were noted, but 
in so far as possible the conditions were made alike for all three places. 

The percentage of spoiling was less in one instance than at the home 
factorv and was somewhat higher at the other place than at either of the 
other two localities. The reason for this difference seems to be plainly in 
the methods employed at the various i)laces. At the factory showing the 
smallest loss, the peas are not brought to the factory on the vines, but the 
pods are picked off in the field, and delivered in baskets. Consequently 
they are not run through a "viner" and exposed to a constant contamination 
from the dust and dirt which are always present on the vines. Another ad- 
vantage of the "podder" lies in the fact that the peas do not get wet and 
sticky from the juice of the vines, but remain dry and so may be more 
quickly and easily cleaned, th.us shortening the time before the peas are in 
the cans. 

.\t the factorv showing the largest loss the conditions were somewhat 
different. The machinery was admirably arranged for convenience, but it 
ajipeared to us rather too crowded to allow of perfect cleanliness. The old 
vines were also allowed to accumulate in large piles close to the factory and 
this we regard as a source of danger. 

Any statement as to the saving of time in processing as a result of clean- 
liness is unnecessary, since every packer knows that a good product can 
only be obtained by the exercise of greatest care and cleanliness. We will 
summarize the conclusions drawn from our experiments as follows : 

Thirty-five minutes at 236 degrees is hardly time enough to completely 
sterilize ipeas when i)acked in the usual way. particularly if they are old and 
hard. At the time now given, when the cans were placed in a favorable 
temperature, a small percentage was found which gave bacterial growlh and 
an acid reaction. 

We would recommend that they be given forty minutes at 236 degrees, 
or thirly-fi\e minutes at 240 degrees. Should any souring occur in goods 
which have been processed at the above temperatures, it would seem to us 
that the peas had soured going into the cans. 

So far as we can determine from the experiments made at diff'erent lo- 
calities, the difference in the keeping qualities of the peas seems to be in the 
cleanliness of factory and machinery, and the celerity with which the goods 
are taken care of. rather than in any quality of the place itself. 



97 



CHAPTER VI. 

In February, 1902, the various canncrs" associations in convention as- 
sembled at ^Milwaukee. The meeting was generally considered one of the 
most favorable ever held, both from a pecuniary standpoint as well as for the 
value of the scientific papers read. 

The question of preservatives in foods having received considerable public 
attention, probably due to the various state food laws and press agitation, 
Professor Prescott was invited to discuss the subject, which lie did in the 
following able manner : 

PRESERVATIVES AND THEIR USE IN FOODS. 

If we comjiarc the processes of food preservation in use today with 
those commonly practiced thirty or forty years ago, we shall find not merely 
a considerable increase in the number of methods thus employed, but also 
an immense development in the application of methods known at that tiine. 
While as a wh.ole the development of these methods has been of great benefit 
to mankind, it has also given rise to some of the most perplexing and difficult 
questions which have ever been put to the sanitarian or hygienist for solu- 
tion, and one of these concerns the use of antiseptics. This particular sub- 
ject has been for a long time a source of much contention, and its satisfac- 
tory solution is far from having been reached at the present time. It may be 
of interest, however, to inquire briefly into the present status of this ques- 
tion, and its bearing upon the subject of food preservation. In order to view 
this matter in its ])ropcr perspective some general statements as to the meth- 
ods and aims of food preservation may not be out of i)lace. It is almost 
unnecessary to state that the general aim in all these processes is the same, 
namely, to prevent putrefaction or fermentative changes, and thus to make 
the surplus of food of one place or one season available in another place or 
at anotlier time, or in other words to guard against periods and regions of 
scarcity l)y conservation of the excessive supplx' in periods and regions of 
abundance. 

Let me first briefly explain the cause and nature of fermentation, putre- 
faction and decay. I'nless some means is taken to prevent, practically all 
foods are likely to undergo certain changes caused l)y the action of extremely 

L-ofC, 99 



minute living organisms, variously known as germs, bacteria, microbes, bac- 
cilli, etc., or by the so-called unorganized ferments. All the chemical changes 
thus brought about by the activity of micro-organisms we sometimes desig- 
nate as fermentation processes, although it is more Qonvenient in general 
to subdivide them into the two classes fermentations and putrefactions. By 
fermentations we mean those changes taking place in sugary or starchy 
foods, the microbes transforming these substances into acids for the most 
part, and thus giving rise to "souring" as in sour corn and sour peas. Putre- 
factions on the other hand are the changes which are brought about by the 
bacteria in the more complex proteid or albuminoid foods, as meats, which are 
rich in nitrogen. Here, instead of the formation of acids, there may be a 
great variety of products, malodorous gases, and other bad-smelling com- 
pounds, and sometimes poisonous bodies, the so-called ptomaines, which 
if taken in with the food give rise to sickness and symptoms of poison- 
ing. The bacteria causing putrefaction live anaerobically, i. e., they do not 
require free contact with the air. Decay is a term sometimes used in a broad 
way to describe any of these processes, and sometimes used in a more specific 
sense to indicate the changes taking place in albuminous matters in contact 
Avith the air, in which case no bad-smelling compounds are formed, unless 
putrefactive processes are going on within the food at the same time. 

Of the processes which may be employed to bring about this conserva- 
tion, we may easily distinguish four kinds of primary importance : 

1. Cold storage. 

2. Preserving, pickling and dr3-ing. 

3. Canning. 

4. The use of antiseptics. 

The desired result may be obtained by the use of a single one of these 
methods, the choice depending upon the character of the food to be pre- 
served, or they may be used in combinations to a certain extent, in which 
case the fourth method is generally combined with one of the others. Let us 
now briefly examine these four methods separately, and determine the under- 
lying principle in each. 

Cold Storage. — It is a well known fact that practically all kinds of food 
"keep" better in the cold than in warmth, and it has become a general prac- 
tice to use ice to assist in the preservation of our daily foods. In addition to 
the convenience and general usefulness, there is a sound scientific principle 
underlying this practice, for \ve find that the micro-organisms of fermenta- 
tion and putrefaction are so much weakened or so stiffened by cold as to be 
rendered inert, and therefore, for the time being, absolutely harmless. Ob- 
viously, this method can be employed only when it is desired to conserve 
materials for comparativelv si'ort periods of time, although with proper re- 
frigerating machiner}' and chambers, some classes of food stufifs might be 
kept forever. This method is of inestimable benefit, for by it we are able to 
keep many foods in the fresh condition for considerable periods, and even 
transport fresh foods for long distances, which would be absolutely impos- 
sible but for the perfection of this process. It should always be borne in 

100 



mind, l^.owcvcr, that refrigeration is not a process of sterilization, for when 
foods taken Irom cold storage are brought again to moderate warmth, 
the processes of decomposition begin as vigorously as ever, consequently 
foods should always be consumed or cooked immediately after leaving the 
cold chambers. Tliis method is then a process of prevention of the growth 
and activity of microbes, not of sterilization. 

Preserving, Pickling and Dryi)ig. — The processes which may be here 
classed as analogous in a general way to the j^rcceding method, inasmuch 
as thev are not sterilizing ])rocesses, but dejiend for their efficiency upon so 
modifying the physical properties of the food substance that bacterial growth 
cannot take place. In order that germs may develop abundantly a compara- 
tively large amount of water is generally necessary, and if the percentage of 
water is diminished, as by drying, the germs are not able to bring about 
their changes until the conditions again become favorable for growth. In 
pickling in brine and ])rescrving with sugar a slightly different action takes 
place, for here we increase the densitv of the medium by the addition of these 
substances which have a strong affinity for water. The dense solutions thus 
formed easily set up osmotic action and tend to absorb more water. When 
microbes come in contact with such substances the water is extracted from 
their bodies and they are thus rendered inert and innocuous. But as with the 
cold storage of foods protection is afforded only temporarily, for if we 
weaken the strength of the brine or sugar sufificiently. we find that the vitality 
of the bacteria has been merely diminished, that in reality we have had a case 
of suspended animation, and fermentative processes will go on vigorously. 

Canning. — We come now to a method of food preservation which is of 
the very highest importance and value. While by the use of the foregoing 
methods it has been possible to establish a temporary immunity against the 
attacks of the fermentation microbes, by hermetically scaling the foods in 
cans or jars and subjecting them to sufficiently high heat we may guard 
permanently against any such invasion. In other words, if we sfcrili.':c our 
footl materials we have no need to fear decomposition or fermentation for 
we have destroyed the cause of such changes. As has been repeatedly pointed 
out by Mr. Underwood and myself absolute sterilization means the killing 
of all bacteria, thus we have here the most nearly ideal of all preservation 
processes in actual use when considered from the fermentation and sanita- 
tion expert's point of view. This subject has already been so thoroughlv dis- 
cussed that further comment at this point is unnecessary. 

i'sc of .Intiscptics or Prcservafivcs. — We come now to the last of the list 
of methods which I mentioned, and the one which must be viewed with the 
least degree of .satisfaction and confidence because of the grave questions as 
to the effect of the chemical substances used as preservatives upon the health 
of the consumers. 

P.y a preservative or antiseptic we mean a chemical substance w'iiicl':, 
owing to its toxic or poisonous action on micro-organisms, is capable of re- 
tarding or preventing fermentation and jnitre faction. If the toxicitv is suf- 
firientlv great to hill the organisms we speak of the substance as a disinfect- 

101 



ant. The distinction between a disinfectant and an antiseptic is then a dif- 
ference in strength and kilhng power, for in very small amounts the strong- 
est poisons act only antiseptically, that is they do not produce the death of 
the germs. Preservatives such as are used in food substances are all anti- 
septic in their character, but it is evident that not all antiseptics can be used 
as preservatives. The preservatives in common use, although sold under 
a variety of names, are in reality comparatively few in number as shown by 
the analyses which have been made from time to time. The most important 
of these are boric or boracic acid and borax, salicylic acid and sodium sali- 
cylate, benzoic acid and sodium benzoate, fluorides, sulphites, and formal- 
dehyde. Borax or boric acid or mixtures of the two are extensively employed 
in the preservation of meats, fish, and dairy products. Salicylic acid and its 
salts are used for fruits and vegetable products chiefly, as jams and jellies 
and in beverages. Sulphites are used in the same food substances as sali- 
cylic acid, and also to some extent for meat. Benzoic acid finds use in bev- 
erages and fruit and vegetable preparations such as catsup. Formaldehyde 
is especially used for milk, and fluorides are used in some beverages, espe- 
cially beer. 

P"rom the authoritative analyses of sixty-seven preservatives it was found 
that thirty-three contained either borax or boric acid as the most active con- 
stituent ; ten contained sulphites ; eight salicylic acid or its sodium salt, and 
seven benzoic or its sodium compound, while the others were either mix- 
tures of the foregoing or were composed of other substances. Analysis has 
also revealed the fact that dealers sometimes sell a single compound or mix- 
ture under different names and at different prices, and often these substances 
are described as harmless and at the same time of the highest germicidal 
efficiency. It may also be of interest to know that all the preservatives com- 
monly used in foods can be easily detected by the skilled chemist in spite of 
the statement sometimes made by agents that certain of their wares baffle 
chemical examination, a virtual acknowledgment that they are to be regarded 
as suspicious. 

But of all the questions relating to the use of preservatives that of the ef- 
fect of the substances which they contain upon the health is of greatest 
moment, and is likewise the most difficult of solution. Generally speaking 
those substances which exert a harmful effect upon bacterial life will produce 
a similar effect upon higher organisms although it may be to a much less 
degree, and this fact forms the basis of practically all objections to the use 
of antiseptics. That is, the general effect of such substances on living things 
is similar, although difi^ering in intensity of action. For example, corrosivfe 
sublimate is one of the strongest bacterial poisons known, and also one of the 
chemicals most deadly for human beings, when taken internallv, and the 
same rule holds good for practically all the substances of very strong anti- 
septic or disinfectant character. Obviously nothing should be added to foods 
which is in itself inimical or poisonous, or which interferes with the normal 
processes of indigestion. And here it should be borne constantly in mind 
that the old saying, "What is one man's meat is another man's poison," fits 

102 



the case exactly. It may be ;)cssiblc, perhaps, for strong", healthy imlivitluals 
in good condition to eat foods containing a small amount of toxic antiseptic 
without suffering any serious consequences therefrom. It is entirely another 
matter, however, when invalids or delicate young children are given such 
foods, and the result is likely to be far from desirable. Further than this we 
do not know with certainty as to the cumulative effect of these substances, 
that is. whether they are readily taken care of and excreted, or whether they 
are retained within the body until considerable amounts have accumulated. 
•We do know, however, rhat in large doses these substances almost in- 
variably act harmfully, and consequently we should be led to believe that ac- 
cunudation would give rise to the same results. To illustrate this in a crude 
way. there is probably no one here who would claim that a single drink of 
whisky would do any one' of adult age and fair health any harm ; on the 
other hand, there is probably no one in this hall who would deny that the 
same amount taken once an hour would seriously damage, and the same 
amount every ten minutes would soon destroy the most robust. On the 
other hand, it is also jiossible to conceive that some of these substances are 
no more harmful than common salt, but this is at least doubtful. 

On reviewing a large number of articles written upon this subject during 
the past two years, I have been very strongly impressed with the inconclu- 
siveness of the arguments presented, and these articles have been written by 
many well known physiologists in Germany, France. Fngland and America. 
For example, Liebreich declares that boric acid and borax have no harmful 
effect when consumed in small quantities, while almost at the same time, in 
another journal, Halliburton asserts that all preservatives should be forbid- 
den by law. Lebbin and Kallman made experiments on animals to show that 
sulphites were absolutely harmless and less poisonous than salt and state 
that the "toxicity of neutral sulphites is a legend." On the other hand. Lange 
and also Cirubcr object to their use on sanitary and hygienic grounds. In a 
similar manner Tunniclift'e and Rosenheim proved to their own satisfaction 
that boric acid, and even formaldehyde exert no harmful action upon healthv 
children, while Kister, in a very carefully conducted research, arrives at an 
opinion diametrically opposite. I could go still farther, and cite other 
examples, but without finally settling the question in dispiUe. Fnough has 
been said, however, to show the present status of the question. In spite of 
the large amount of work which has been bestowed upon this question the 
discussion and experimentation have hardly passed beyond the academic or 
theoretical stage, and there is great need for the more practical demonstra- 
tion before we should accept the use of these substances as harmless. I be- 
lieve it to be the wise course to regard every chemical preservative as guilty 
until proved innocent. A little thought will show Ik^w ditificult accurate, re- 
liable experimentation must be in this matter, for a living body is a far more 
variable reagent than a chemical solution and, moreover, different individ- 
uals or animals luust of necessity react differently according to their state of 
health, powers of digestion, occupations, and so forth. Then it will be neces- 

103 



sary to make an enormous number of observations before the matter can be 
regarded as settled. 

It is true that there is a class of food products such as ham, bacon, dairy 
products, jams, etc., of such character that their flavor or usefulness would 
be destroyed by heat. For such foods harmless ^preservatives would be of 
inestimable value, and use of preservatives in such foods has a poor excuse 
on the ground that the antiseptic is necessary to prevent decomposition, m 
such cases every package should be plainly labeled with the name of the 
antiseptic it contains, in canned goods, on the other hand, the use of any 
antiseptic shomd be unhesitatingly condemned, for it is absolutely unneces- 
sary u the food has been properly prepared and sterilized. Addition of any 
preservative to canned foods is a virtual acknowledgment that the packer 
does not know his business, and their use can only be regarded as a make- 
shift to cover up slovenly, uncleanly and inefficient methods. The absence 
of preservatives in canned goods is an indication of good, intelligent man- 
agement, cleanly methods and wholesome food as a rule. On the other hand 
their presence shows the reverse characteristics and a tendency to careless- 
ness and sloppiness on the part of the manufacturer, for if a manufacturer 
depends upon the use of a preservative to ensure the keeping quality of his 
goods, he is putting a premium upon inefficient and careless work. 

Whether preservatives are ultimately proved to be injurious or otherwise 
their use in canned goods should never be allowed for the simple reason 
that they are unnecessary if the goods have been properly prepared. 

In the different States there are numerous laws regulating the use of 
these chemical antiseptics in foods. As these laws are different, a man 
might conceivably be acting within his rights in one State and violating the 
law by selling his product in another. At the present time the only way to 
be sure of being on the right side is by abstaining entirely from the use of 
antiseptics, for here as in all things else total abstinence is the only absolutely 
safe method of keeping out of danger. 

It is probable, perhaps, that their use cannot be entirely prevented, conse- 
quently a national law regulating the use and restricting abuse of such sub- 
stances is most to be desired. That this subject is of international or uni- 
versal interest is made evident by the amount of discussion which has been 
given to it in England and on the continent. The latest contribution is in the 
report of the committee appointed by the British government to investigate 
the use of preservatives and coloring matters in foods, and which has been 
recently published. The report of the committee is on the whole unfavorable 
to the use of preservatives, recommending that certain ones be entirely pro- 
hibited and that others when used at all should be only in extremely small 
quantities, certain maximum limits being set, limits so low, by the way, that 
there might almost be doubt in some cases as to whether any preservative 
action at all would take place. It is interesting to note that the report insists 
that no preservative of any kind should be used in any dietetic preparation 
intended for the use of infants or invalids, and also prohibits the use of cop- 
per salts in "greening" of vegetables, although one member of the committee 

104 



demurred fruiii lliis judgment. Comment upon this excellent report is almost 
unnecessary, except to say that it emphasizes anew the unsettled state of the 
question and the necessity for much further experimentation before anything 
like a final verdict can be pronounced. 

The prohibition of the use of preservatives in foods designed especially 
for infants and invalids betokens some susi)icion on the part of the committee 
that there is no chemical ])reservative which is not objectionable under some 
circumstances. 

In conclusion let me reaflirm the necessity for more information upon this 
important subject. I believe it would be wise for such bodies as this associ- 
ation to take whatever steps may be within their power, toward further in- 
vestigation, either by agitation for a national court of inquiry similar to that 
recommended by the English report, or otherwise. The agricultural depart- 
ment has already done much in this direction, but more could be done if the 
manufacturers of such foods would show a spirit of something more than 
selfish interest, and use their power to further the work. In my opinion, 
such action on their part would be fully repaid, even in a financial way. And 
especially let me empliasizc again that the two best agents for preservation 
of foods that are at our disposal are cold and heat, cold for the fresh foods 
which are to be kept temporarily, and heat for the greater and ever-increasing 
class of canned goods, which can be kept for any length of time and in all 
climates, and which already plays so important a part in the nutrition of the 
world. If the producers of canned foods are wise, they will study to secure 
complete sterilization by heat, cleanliness, rapidity and economy of produc- 
tion, and intelligent, scientific management of their factories. They will 
thus have no use for preservatives, but will regard them as undesirable be- 
cause absolutely unnecessary, for there is no valid reason that can be sug- 
gested for the addition of a substance of dubious influence upon the health 
of the consumer to what should otherwise be regarded as a pure food of the 
highest value. 

THE ECONOMIC AND SANITARY IMPORTANCE OE CLEAN- 
NESS IN THE CANNED GOODS INDUSTRY. 

Mr. \\'. Lyman Underwood of the Massachusetts Institute of Technology 
read his address to the convention, illustrated bv stereopticon views, whicli 
was listened to with much interest by the convention. Mr. Underwood spoke 
as follows : 

When 1 entered tb.e banquet hall last evening I felt something like a cold 
chill on finding the name of L'nderwood on the program as having something 
to say about "'Those Who Can and Do." I had made no preparation and 
felt quite cheap, and did npt know what I could say about "Those Who Can 
and Do." The onl\- thing that canre into my mind was an old Scotch saying, 
"Granny, a man may can all the corn he can. but the canner can not can a can." 
I found later that th.cre were other I'nderwoods tlian myself and I was not 
called on at all. 

105 



Thanks to the science of Bacteriology, which has made such rapid strides 
in the past few years, there should be no longer any uncertainty as to the 
reasons why spoiling sometimes occurs in certain canned goods. The science 
has shown us that such deteriorations are due to the" presence of minute 
organisms variously known as micro-organisms, germs, microbes or bacteria. 
They comprise the lowest and smallest forms of life. So small, indeed, that 
thousands might find standing room, so to speak, on the point of a cambric 
needle. It was previously thought that these lower forms were generated 
by decomposing organic matter which, in some unaccountable manner, had 
the power to spontaneously produce this type of life. 

It was even believed that putrid meat had in itself the property to produce 
worms or maggots. Many years ago they went even further. Someone 
claimed that, given a quantity of dirty rags and some pieces of cheese or 
crumbs of bread, mice could be spontaneously generated. 

For many years a fierce conflict waged between the upholders and disbe- 
lievers in this theory of spontaneous generation ; until Pasteur, by a series 
of continued experiments carried on for many years previous to 1880, demon- 
strated beyond all possible doubt that these lower forms of life could not 
be generated anew, but must always come from previous existing life. By 
these experiments he showed how easily these germs could come in contact 
with all organic matter and as a result of these discoveries better methods 
have been devised by which it is possible to guard more thoroughly against 
the action of germ life. 

One of the principal weapons of defense against this bacterial action is 
the practice of most scrupulous cleanness, and in no other industry does this 
factor play a more important part than it does in the preservation or canning 
of food products. While, no doubt, it is generally considered that cleanness 
is a most desirable state in any manufactory there are certainly more import- 
ant and vital reasons why such a condition should exist in the operation of 
this business than in many others. No manufacturer cares to see his factory 
in a dirty condition, if from no other than aesthetic reasons. The presence 
of dirt and disorder, even if no direct hindrance to the proper performance of 
any business, is certainly an ofi:"ense to the eye. In factories where a lack of 
order and cleanness exists the operatives will be likely to form their habits 
and carry on their work in a manner somewhat corresponding to their sur- 
roundings. In the canning industry, however, cleanness is necessary from 
other and more weighty considerations than the mere aesthetic ones, and it 
is the purpose of my paper to show why this is so and to make some sugges- 
tions bearing on the subject, which I hope may be of interest. 

The fundamental principle involved in the preservation of food in cans 
or other hermetically sealed packages is the exclusion of all germ life from 
contact with the food material in such manner that it shall be impossible for 
any germs to gain access to the contents of the package. In order to remove 
all bacterial life which, under ordinary conditions, is everywhere present, 
especially upon food products, heat is employed as a means of sterilization 
and through this agency these lower forms of life, the active principle of all 

106 



decay and icnncntatiun, may be killed. While all bacteria may be readily 
destroyed by the proper application of heat, as has already been pointed 
out in the previous papers read before you by Mr. Prescott and myself, it is 
important to know just what temperature is necessary or how long a given 
temperature should be applied to overcome the specific organism which is 
concerned in any particular food to be preserved. Some microbes are much 
more susceptible to heat than others. Many of them will succumb to a tem- 
perature of 200 F., while others will survive after many hours of cooking at 
a boiling temperature. Fortunately the pathogenic or disease germs belong 
to the class which are easily killed ; unfortunately for the packers, however, 
the germs which are most liable to cause trouble in their industry are those 
which arc the most resistant to heat. To overcome some of these more 
tenacious germs may require a more intense or longer continued heat than is 
practical to use without over-cooking and thus injuring the flavor of the 
food. Under these circumstances it is easily seen how absolutely necessary 
it becomes to use every precaution in preventing, so far as possible, any 
bacteria from coming in contact with the food before it is put into the cans. 
The particular danger to be apprehended is that the germs may be easily 
transmitted to the food through the agency of dirt ; for dirt is the principal 
vehicle bv which bacteria may be readily conveyed. 

In this pajier we shall consider as dirt not only soil and earth, but, in ad- 
dition, those substances from whatever source which become of significance 
because of their possibility to act as carriers or transmitters of bacterial life. 
Broadly speaking dirt may be well defined as matter out of place, and under 
this general heading might be included material varying quite widely in 
character and originating from very dififerent sources. This definition is 
much broader than the generally accepted one that classes dirt merely as soil 
or earth, and regards it as matter entirely without life. The common o]Mnion 
that soil and dust are lifeless matters is an erroneous one. In reality "it is 
one of the most marvelous revelations of bacteriology that the earth long 
regarded as the type of lifelessness is in fact at least in its uppermost layers 
teeming with life, containing vast hosts of micro-organisms more abundant 
by far tlian the grains of sand upon which they dwell. A single gram of gar- 
den soil (approximately half a teaspoonful) may contain millions of micro- 
organisms." 

So long as these bacteria remain upon the ground as a part of the soil they 
are very beneficial, for they constantly help to decompose organic matter and 
change it into food for vegetation. When, however, they gain admission to 
the factory and bring about decomposition of the rich food material upon 
which they may be deposited, unless destroyed by thorough sterilization (for 
manv of them have great resistance), they will cause changes, fermentation 
and bad flavors. 

It may be even possible, provided the weather is warm or if the cans 
stand around for a considerable time before they go to the retorts, for the 
germs to grow sufficiently to produce some undesirable change before the 
final processing. It is thus readily seen how easily these conditions may 

I07 



cause economic or financial loss. It might be wondered how these organisms 
could gain access, in any considerable numbers, to the factory. The problem 
is a simple one, however, when it is considered, as has already been stated, 
that the upper layers of the earth are so densely populated with germ life. 
In dry weather any current of air will lift more or less dust, conveying it to 
distances varying with the strength of the wind and with a strong breeze the 
number of bacteria so carried may be enormous. 

In some experiments conducted by Professor Sedgwick, at the Massa- 
chusetts Institute of Technology, it was found that in a gallon of air taken 
(luring a dust storm, five feet above the surface of a macadamized road 
there were present approximately 100,000 bacteria. Thus it will be seen 
how easily this type of dirt, which we may call earth-dust, containing its vast 
numbers of bacteria, may, under favorable conditions, get into the factory. 
To minimize the danger from this source it is important to do away, so far 
as possible, with all conditions about the factory and immediate vicinity 
which tend to give rise to dust. Sowing grass and keeping a good turf about 
the building and using as little area as possible for roadways, and keeping 
these well watered will do much to mitigate this evil. 

Still another type of dirt frequently gives rise to further trouble, the 
source of which lies in the uncleanly habit of allowing refuse, as for example, 
pnes of corn-cobs or pea-vines and pods, to accumulate close to the factory. 
In warm weather this refuse, quickly fermenting, generates millions of bac- 
teria and attracts countless numbers of flies, who, feeding upon and walking 
over the fermenting material, may carry away these germs upon their feet. 
Flying into the factory they now infect any food material upon which they 
happen to light. An illustration of this fact will be shown you later by the 
stereopticon. 

It may not be out of place in this connection to say a few words in regard 
to the common house fly, when it is seen how easily tKis insect may become 
a menace to the packer, aside from the fact that it is always an unmitigated 
nuisance to everyone. Dr. L. O. Howard, chief of the Division of Ento- 
mology at Washington, D. C, states that 99 per cent, of the flies which are 
found about houses and stables are the ordinary house flv, Musca 
Domestica. which occur in enormous numbers and are wonderfully prolific. 
An individual fly lays on an average about 120 eggs, which in a few hours 
hatch into larvae or maggots. Then, after another transformation, at the 
end of ten days becomes eventually the full grown adult insect. It has been 
found that these flies breed almost exclusively in horse manure, as fully 95 
per cent, of all of them come from this source and experiments have shown 
that a single pound of horse manure will produce 1,200 flies. 

It will be seen that it is dangerous to allow such waste material to ac- 
cumulate about the factory. The remedy in this case is an obvious one. Get 
rid of such refuse at once. To be freed of the flies, however, is not so 
simple a matter, although a complete removal of all waste material will, no 
doubt, cut down their numbers considerably. If there are many horses used 
in connection with the establishment or stabled in the near vicinity, the plac- 

108 



ing of tly-screens around the manure i)its will effect a ratlical change in the 
conditions by keeping- out the tlies from their natural breeding-places. The 
liberal use of chloride of lime sprinkled over the manure, where it is not 
practicable to use screens, will tend to produce the same result. 

Having considered the piincipal sources from which germs may be 
brought into the factory from the outside, it now remains to take up the 
liability of trouble occurring through a lack of cleanness within the fac- 
tory. It is hard to say which of these two sources is the more important for 
in many ways they are dependent on one another. The greatest danger in 
the factory and probably the most common one arises from dirt in the 
form of fermenting food material. For example, in the canning of sweet 
corn, any kernels or milk of the corn that happen to be left upon the floor or 
on the cutting, silking and cooking machines or upon the utensils used to 
convey the product about the factory will quickly ferment. Each particle 
now becomes a centre from which germs may be further distributed, until 
as with yeast in bread making "A little leaven leavencth the whole lump." 

The rapidity with which these particular microbes will multiply under 
favorable conditions is shown by the experiment which was described in the 
paper on Sweet Corn, written by Mr. Prescott and myself. I may be par- 
doned for repeating it for it illustrates this point very strongly. Into each 
of two cans of fresh corn was placed a very small drop of liquid containing 
some of the bacteria obtained from kernels of corn. These cans were then 
sealed and put in a warm room at 9 o'clock in the evening. At 6 next morn- 
ing it was found that at some time during the nine hours intervening both 
cans had swelled and burst, literally tearing the entire top from the cans and 
covering the ceiling with kernels of corn. 

Similar results have been observed in the packing of peas ; in fact the 
growth of germs in this case may be even more rapid than with corn, and it 
is no doubt the principal factor concerned in producing the peculiar tlavor in 
sour canned peas. 

To guard against the danger from fermentation of raw material which 
has been left upon the machines or scattered about the floor, it is necessary 
to give frequent and thorough washings to utensils as well as machines and 
floor, using liberal quantities of scalding water or live steam at least twice a 
day. In well-managed factories wdicre this is already the custom, the excel- 
lent results well repay the additional labor. 

In the packing of peas the ordinary method of removing them from the 
pods by the viner machine introduces another complication. It is hard to 
imagine a more fruitful source of contamination than that afforded by this 
machine. Vines and leaves, pods and peas, just as thcv are cut and brought 
from the fields, are run through it. and by revolving wooden paddles the peas 
are thrashed out from the pods. Dust and dirt abound, and must of neces- 
sity come in direct contact with the peas. Nevertheless, by the use of this 
machine such a tremendous amount of labor is saved that it is hard to see 
how it could be dispensed with, as the shelling of the peas bv hand would be 
a most expensive and slow operation. 

I09 



Ihe only remedy to be applied under the circumstances is to scald the 
peas at the earliest possible moment after they come from the viner. This 
will check the growth of most of the bacteria, and if promptly done no bad 
flavors should develop, provided the heat in the final process be high enough 
for thorough sterilization. 

The remaining danger of contamination to be considered is that arising 
from the dirty hands of the employees ; but this defect is easily remedied, 
where it exists — and there is really no excuse for its existence. Men| 
women and children who will not conform to cleanly habits should have no 
place in a canning establishment. Their room is far better than their com- 
pany. 

Encourage their keeping themselves clean by providing them with suit- 
able and convenient toilet rooms, well supplied with soap, water and clean 
towels. Cleanness and order from attic to cellar will invariably induce 
cleanly habits with all who labor under the same roof, and employees will 
soon take pride in working under such conditions. 



1 lO 



CHAPTER VII. 

Professor I'orlx-s of the Illinois State I'liivcrsity rciul the following' 

CONTROL OF INSECT IXJLKV TO CORN. 

paper on the above subject at the annual canncrs' meeting" held at Detroit 
February, 1900: 

Professor Forbes spoke as follows : 

The subject of corn insects is very complicated, one which has been in- 
vestigated by students for many years. The time I have spent upon it 
myself is more easily reckoned in years than in months. I can touch only 
upon a few cursory points in corn culture. I can speak of only a few 
of the preventive measures which everyone should know who is interested 
in this subject, and illustrate my remarks by a few drawings of the leading 
corn insects. 

The struggle between man and the insect world, begun long before the 
dawn of civilization, has continued without cessation, and will continue, no 
doubt, as long as the human race endures. It is due to the fact that both 
men and insects want the same things at the same time ; its intensity is 
owing to the vital importance to both of the things they struggle for; and 
its long continuance is due to the fact that the contestants are so equally 
matched. We think of ourselves as lords over nature and masters of the 
world, but insects had thoroughly conquered the world and taken full 
possession of it long before man began the struggle. They had consequently 
all the advantage of a possession of the field (which is nine points of the 
law) when the contest began, and they have disputed every step of our 
invasion of their ancient domain so persistently and so successfully that 
we can even yet scarcely flatter ourselves that we have gained any very 
important permanent advantage over them. Here and there a truce has 
been declared, a treaty made, and even a partnership established which is 
advantageous to both parties to the contract — as with bees and silkworms, 
for example — but wherever their interests and ours are diametricallv op- 
posed, the w'ar still goes on, and neither side can claim the final victorv. 
It thev want our crops thev still continue to help themselves (o them: if 
they V\\e the blood of our domestic animals, they pump it out of the veins 
of our c.tmIc and our horses at their leisure and under our verv eves; if 



tl.'ey choose to take up their abode with us, we cannot wholly keep them 
out of the house we live in, we cannot protect our very persons from their 
annoying and even pestiferous attacks, and since the world began we have 
never yet exterminated, we probably never shall exterminate, so much as 
a. single msect species. They have, in fact, for ages inflicted upon us the 
most serious evils without our even knowing it. It is the cattle tick which 
keeps alive and propagates the Texas fever; it is the mosquito which 
inoculates cur blood with malaria ; it is the house-fly which carries to our 
food the typhoid-fever germ, and now that we have begun to discover facts 
of this order, it is likely that many more such instances will be brought to 
light. Not only is it true that we have nowhere really won the fight with 
the world of insect life, but we may go further and say that by our agri- 
cultural methods, by the extension of our commerce, and by other measures 
connected with the development of our civilization, we often actually aid 
them most efficiently in their contest with ourselves. Our rapidly growing 
world-wide commerce in fruits and grains, for example, our importations 
of new plants from the remotest regions of the earth, and our exports of 
our own best varieties in turn, have the practical efifect to establish a general 
international exchange of injurious insects such that we are apparently 
certain to become the eventual prey of every insect species living anywhere 
on earth that can do us any harm. 

To the attacks of these associate insect enemies, native and imported, 
the corn plant is in some respects seriously subject. In the first place it 
belongs to the great family of the grasses, to which nearly all the other 
farm crops, whether of grain or of forage plants, also belong. An Ameri- 
can farm, except for the garden patch and an occasional field of clover, is 
usually an unbroken area of a few kinds of grass ; and as several of our 
worst insect pests feed on the grass plants generally, Indian corn is ex- 
posed with the rest to the principal enemies of all. The wireworms, the 
cutworms, the white grubs, the army worm, the chinch-bug, the turf web- 
worms, and the grasshoppers are all general grass insects which can find 
an abundant means of support anywhere and at any time, and which mul- 
tiply without hindrance on almost any farm, and all are peculiarly destruc- 
tive to Indian corn. Our pastures and meadows are, in fact, the great 
feeders and breeders of the worst corn insects. 

Other serious difflculties are due to a common farm rotation, in which 
corn follows upon grass. In the turf of our pastures and meadows the 
principal grass insects may exist in considerable numbers without pro- 
ducing any very considerable efifect on the abundant vegetation which 
carpets the ground and grows rapidly to make good any injury; but when 
corn follows on this infested sod, all the grass insects which come through 
the winter in a destructive stage, emerging in spring hungry from their long 
fast of hibernation, find no longer the abundant feast of a grassy turf pre- 
pared for them, but only the sparse vegetation of a field of sprouting corn, 
and on this, of course, they concentrate for its destruction — more or less 
comnlete. The cutworms, the wireworms. and the white grubs are ex- 
amples. 

1 12 



Then besides these insect enemies common to the grasses, the corn plant 
has its own special list of dependent insects (such as the corn rooc worm 
and the corn aphis), which do little or no harm to any other valuable plant. 
As the so-calle(,l corn belt of America is a comparatively limited region, 
Indian corn is always a very prominent crop there and must become more 
prominent with each decade. This permanent devotion of a vast area 
largely to a single crop otters the best conditions possible for the inordinate 
multiplication and general distribution of these special insect enemies ; and 
hence we have seen the two species just mentioned rise witliin the last 
thircv vears from entomological rarities to agricultural pests, and we have 
been able to trace the extension of their injuries year by year to regions in 
which the\ had been previously unknown. 

There is another source of difliculty and danger which tlie corn crop 
shares with some of the other principal crops of the farm, and that is a 
variability and uncertainty of entomological injury sucii tliat the ordinary 
corn grower will trust to luck for the safety of his crop rather than use 
either svstematic precautions or special measures of prevention. If insect 
injuries were practically the same year after year, all would learn to guard 
against them, but since they may range from nothing to a hundred per cent, 
the farmer speculates on his chances of immunity, saving thus each year 
a slight expense and trouble, but incurring thereby a certainty of ultimate 
heavy loss. A correct general policy in respect to agricultural injuries by 
insects is a measure of crop insurance, but premiums must be paid in year 
by year, otherwise the policy lapses. 

A general difficulty related to the foregoing and, like that, subjective to 
the farmer instead of objective to the insect or the crop, is due to this 
same general disposition to speculate instead of insuring. The farmer is 
necessarily and at best a great speculator. His profits always depend upon 
so many n.iforeseen and uncontrollable contingencies that from the day when 
he puts l,is seed into the ground until he pockets the proceeds of his labors 
and investments, he is practically betting on the occurrence of series and 
combinations of lucky accident. His tendency to bet on his luck is thus 
likelv to liecome inveterate, and clings to him under circumstances where 
he should see that the game is already going against him. Then when 
general conditions are peculiarly favorable to an insect outbreak, he never- 
theless frequently bets that all signs will fail, and that this time he will 
surelv escape; and even after the outbreak has begun he may persist in 
betting that it will presently cease without doing him serious harm, so the 
time for efficient action is passed in optimistic speculation and the disaster 
becomes irremediable. 

In fact, api^lying these remarks to the economic entomology of the corn 
field, we may say that in this field all disasters are irremediable. When an 
insect attack on corn has become serious enough to arouse apprehension, 
it is almost invariably too late to arrest it. There are no remedies, generally 
spe.iking. for the entomological diseases of the corn crop, and we are limited 
in our practice to hygienic, that is to preventive, measures only. 

As an illustration of these preventive measures, to the vahie of which I 

113 



shall have frequent occasion to refer in llie detailed discussion of injurious 
insect species presently to follow, 1 may mention a suitable general scheme 
of crop rotation. Throughout the greater part of my own state the favorite 
and long established rotation system is that in whicii grass, coxa, and small 
grain follow each other more or less rapidly in the order named and in 
uninterrupted succession. Now what I have said of the injuries to corn 
due to insects bred in pastures and meadows must have already suggested 
to you the defective character of this rotation scheme from the standpoint 
of the economic entomologist. It is a scheme for the rotation of crops but 
not of crop insects. From grass to corn and from corn to small grain the 
same species carry over more or less completely and do a continuous injury, 
gradually diminishing in number, it is true, until the return to grass, but 
then rapidly regaining all their old abundance. What is needed is a varia- 
tion of this rotation such as will break the vicious circle by the insertion of 
some crop not belonging to the family of grasses, and hence not likely to 
attract and breed the principal grass pests. And it is best that this should 
be a forage crop since, as I have already said, it is the forage grasses which 
furnish the great feeding and breeding grounds of the corn insects gener- 
ally. A system then, in which pastures and meadows of blue grass, timothy 
and the like, should lie as long in grass as practicable, not entering into the 
ordinary grain rotation, but in which this rotation should consist of corn, 
small grain, and clover in continuous succession, would meet the conditions 
mentioned. 

Then when the old grass lands are finally broken up for corn, special 
measures must be taken to clear them, so far as practicable, of hibernating 
insects before breaking, and clover or some other crop not itself a grass 
must, whenever practicable, be introduced before the ground is planted to 
corn. A very early fall or late summer plowing of the turf will prevent 
the appearance of cutworms in the field the following spring, and pasturing 
by pigs previous to plowing will destroy the greater part of the white 
grubs and wireworms living in the sod. Another measure of prevention, 
to which also I shall have occasion to refer again, is an early change of 
crop on corn land, such that the special corn insects shall not have too 
long a period in which to multiply up to destructive numbers. Signs of 
danger, recognizable by an intelligent observer, will presently be described ; 
signs which call for an immediate shifting of corn culture to some other 
ground. 

The corn insects recognized in the Eastern United States as in some 
way and to some extent injurious to some part of the plant number 214 
species, of which 18 are known to infest the seed, 27 the root and the sub- 
terranean part of the stalk, 76 the stalk above ground, 118 the leaf, 19 the 
blossom — that is the tassel and the silk^ — 42 the ear in the field, 2 the stacked 
fodder, and 24 the corn in store, either whole or ground. The greater part 
of this long list, which is doubtless by no means really complete, is com- 
posed of those whose injuries are now so slight or so rare as to constitute 
a possible menace rather than to cause a serious loss ; but the history of 
economic entomology, and even of the entomology of this plant, teaches us 



114 



iliat \vc can rarely icll in advance what to expect of any possibly injurious 
species. In fact some of the insect enemies of corn now most destructive 
were not many years ago almost unknown even to the entomologist — the 
northern corn root worm and the corn root aphis, for example. 

'J'he principal insect species infesting this plant are the wire worms, at- 
tacking the seed ; the same insects, the white grubs, the corn root worms, 
and the root aphis, affecting the roots ; the cutworms and root web-worms, 
the armv worm, the corn worm, the bill-bugs, the chinch-bugs, and the 
grasshoppers, injuring stalk and leaf; the corn worm, the corn root worms, 
and the grassluipjiers eating ih.e llower structures and the ear; and the meal- 
moth and the weevils devouring the kernel in the granary or the meal in the 
bin. Uf these by far the worst at present are the wireworms. the corn root 
worms, the white grubs, the root lice, the cutworms, ilie chinch-bug, the 
corn worm, the grasshoppers, and the army worm. 

Here are some drawings showing the northern corn root worm. Jt 
is a small worm which bores its way lengthwise in the young roots of the 
corn ; it leaves behind a brownish colored trail in the passage way it eats 
through the root. * By examining the roots of the young corn you will dis- 
cover this. Of course the plants arc weakened; those that are attacked 
have a stunted growth. 

The corn root aphis is closely associated with the common brown ants 
found in corn fields. The ants collect the eggs in the fall and take them in 
their burrows in the ground, and there keep them all winter. In the 
spring thev carefully watch the eggs; on warm days they are brought to 
the surface of the ground where they will be wanned by tiie sun, and at 
night are taken underground again, to protect them. J5y digging up in 
some corn field you may find in the ant's nests in early spring (piantities of 
these eggs. As soon as the eggs are hatched they are taken by the ants 
and placed on the young roots of the growing corn ; in themselves these 
insects or lice are helpless, and very sluggish in their movements. They 
feed on the tender roots of the corn ; the ants are benefited in this way ; 
the\- live uj^on a sweetish exudation from two tubes, one on each side of 
the lice at the posterior i)ortion of the body ; the ants themselves do not 
touch the corn, as many think, but simply live upon this sweetish substance 
from the a]ihis itself. The manner of reproduction is as follows: All the 
eggs which hatch in the spring arc all females ; the young are born alive, 
there being no eggs. They mature in about u to 14 <lays. and begin rcjiro- 
duction immediatelv. The r.umbcr which coidd be produced from a single 
one of these lice, if there were no checks u])ou the number reproduced, is 
simplv enormous. We estimated it once, and after taking measurements 
of the insects we found that the lice produced from a single one. in the 
course of a season, if reproduction was carried on at the same rate they 
are capable of. would ]iroduce a sufficient number to make a path ten feet 
wide and fiftv miles long. While during the spring and summer only 
females are produced, and these arc liorn alive, in the last generation in the 
fall there arc both males and females brought forth ; lhe\- i)air then as other 



1 i.s 



insects do and the eggs are laid, which are collected by the ants, as above 
stated. 

Here you see the white grub, and its egg, going through the various 
stages. Here is the pupa, and then the brown beetfe which you have all 
seen in the fall. Both the wire worm and the white grub are grass insects. 
The white grub lives three years before it completes its transformations, 
so that the second year after the grass has been planted in the corn field 
there may still be found great numbers of these insects, the white grub and 
the wire worms; frequently the greatest injury is done the second vear, 
so that it will not be safe even then to plant corn in a field which has been 
infested with them. The point I wish to make regarding these is that for 
the proper protection of the corn there should not have been corn in the 
field for two or three years previous, on account of the length of the life 
of these insects ; clover should be substituted. 

The root web worm is a cut worm ; they result from eggs laid by 
moths in the fall, and complete their transformations in a single year ; the 
eggs are laid in grass lands, and where there is no grass upon the ground 
the eggs are not laid. If the ground is plowed early the young have such 
a long time to live before there is anything for them to feed upon they will 
perish before there is food for them. 

If you see rows of little holes in the leaves of corn, made very regularly 
as to size and position, like these shown here, you will know that they are 
made by the bill bug. These punctures are made when the leaf is young, 
and folded up so that all these punctures were made by one incision of the 
sharp bill of the insect, going through the several layers of the folded leaf. 
As the leaf unrolls in the course of its growth, the punctures appear side by 
side as illustrated ; and these long punctures are caused by the growth in 
length of the leaf, the holes extending in length as the leaf grows. These 
bugs are very destructive ; they are bred mainly in grass lands ; the larvae 
will have on a single stalk and top of timothy sufficient food to bring it to 
maturity. 

Here we have the several stages of the cliinch-l)ug ; the eggs are depos- 
ited in May on the roots or lower leaves of the corn. They shed their skin 
four times, and each time the general appearance of the insect is changed, 
making five stages. There are two generations in a year. Some live on 
the wheat and others on corn. We have demonstrated the practicability 
oi the destruction of the chinch-bug to prevent it doing injury to corn. 
At the harvest period most of these bugs have not reached maturity ; some 
have of course, but not very many. And not yet having wings they cannot 
make their way from one field to another ; they concentrate upon the outer 
rows of corn along the field. They do not know the use of wings at first, 
and crawl along the ground, helplessly, in rows. The chinch-bug lives upon 
nothing but grasses ; it cannot live upon anything else. We have found 
in experimental work and also in practice that this insect can be destroyed 
as it makes its way out of the field, at a very small expense. We killed all 
the chinch-bugs in a 20-acre field of wheat, as badly infested with this 

1 16 



pest as any field can l)e, ai an expense of abuui 50 cenls per bushel, and wt 
•gathered about 13 bushels of these insects from the field. We measured a 
(luantity of them and estimated that there were about 8,000,000 of them to 
tlie bushel. The total expense of doing this was about $5 or $6, and we 
yaved the lield adjacent to this one. The process is a combination of the 
various methods in use into one. You have probably heard of the "dusty 
furrow" ; these bugs cannot crawl over this furrow, made by dragging a 
log around in the furrow until the earth is made into a fine dust ; they simply 
roll l)ack when the\- attempt to climb up. Of course if a shower comes and 
moistens the earth, the dusty furrow is spoiled, and then they can go over. 
Another method is to pour a small stream nf tar aroinid the field. This 
will effectually arrest the progress of the grub. At intervals of about 20 
feet in the dusi\ fiuTow the farmer can take a post-hole cligger and dig 
holes of a slight depth, and the bugs will accumulate in these holes, where 
they can be killed by the use of a little kerosene. 

Let me now reca])ilulate the economic recommentlations of this dis- 
cussion. 

1. There is, generally speaking, no remedy for the attacks of the corn 
insects, and we are compelled to depend on measures of prevention only. 
Exceptions to this statement are offered by sudden invasions of the corn 
field from without l)y insects moving together on foot, such as the army 
worm and the chinch bug. The progress of these insects may be arrested 
bv barriers interposed across their line of movement, and their destruction 
at such barriers as thev accumulate there. Preventive measures are either 
general precautions to be applied without reference to locality or tempo- 
rary condition, or special precautions to be used when special danger 
threatens. The former are generally measures of farm management, such 
as the rotation and selected succession of crops, and the choice of times for 
the plowing and the planting of the field. The latter are special variations 
of the usual management called for by unusual circumstances, such as the 
appearance in the ipield in fall of notable numbers of the beetle, of the corn 
root worm, or noticeable injury to corn by the wireworms in the spring 
of the first year after grass. 

2. The use of clover instead of grass in the ordinary rotation of the 
farm will greatlv reduce injuries to corn by wireworms, white grubs, cut- 
worms, and turf web-worms, and the insertion of some other crop between 
grass and corn when a change from one to the other must be made, will 
reduce losses bv insects under these circumstances to a mininumi. Tastur- 
ing grass lands bv i)igs in summer and early fall before the sod will be sim- 
ilarly serviceable. 

3. The verv earlv plowing of grass lands — that is in late summer or in 
earlv fall — will prevent attack by cutworms and web-worms ui)on the crop 
of tile following spring, except as these insects mav invade a field to some 
extent from without, and fall plowing of land infested by wireworms will 
tend to prevent the transformations of those insects to the beetle stage, and 
will thus help in a general way to keep their numbers down. 

4. Frequent change from corn to some other crop on the same ground 



1 17 



will diminish loss by the corn root aphis and prevent that by the corn root 
worm. Such change becomes imperative if the crop has suffered notice- 
ably from the latter insect. 

5. The chinch-bug may be so far kept out of the c'orn field as to make 
its injuries to corn comparatively insignificant by a combination of the 
dusty furrow and the coal-tar strip reinforced by post-holes, with kerosene 
emulsion reserved for use if this compound barrier is locally passed by the 
bugs. A still simpler form of this barrier method will serve for the exclu- 
sion and destruction of the army worm. 

6. For the injuries of the corn worm we have as yet no preventive or 
remedial measure of any special value, but there is some theoretical reason 
to believe that fall plowing of corn ground will act as a gradual check upon 
them. 

Finally, if w^e scan this program of operations and list of expedients we 
shall find them not only practicable at little additional cost to that of the 
ordinary management of the farm, but actually beneficial, as a whole, to 
the crop and to the farm itself irrespective of their utility for the prevention 
and control of insect injuries to corn. In fact, the conclusions and require- 
ments of the economic entomology of this crop powerfully support the 
requirements of an intelligent agriculture, and if the insect enemies of corn 
do nothing more for us than to popularize the culture of clover as a substi- 
tute for the edible grasses and to enforce a frequent change of crops on 
the same ground, I think that they will in the end deserve blessing instead 
of cursing from the American corn farmer. 

Prof. Forbes then answered questions of members regarding points 
brought up in his address. He said a fall plowing would not diminish all 
of the pests referred to, although it would some of them. By removing the 
fodder from a corn field and the next year replanting it with corn, will 
help to diminish a number of insects which interfere with those 
who raise corn for canning purposes. Fall plowing of infested fields 
breaks open the cells of the pupa and the insect is thus exposed to the 
weather, and they are not likely to survive the winter if exposed in this- 
way ; that is about the only benefit I know to be derived from fall plowing, 
along this line. A second plowing in the spring would undoubtedly be of 
benefit. Some sections are troubled with the corn root worm, and the 
farmers find that heavy fertilizing with manure helps the corn ; but in 
such cases the increased growth of the corn is undoubtedly due to the 
effect of the fertilizer upon the corn, rather than any effect upon the worm. 
in the way of destroying the worm. Because the next year there will be 
more worms than before. The best way to get rid of them is by rotation of 
crops, as I have said. The damage is less in wet years than in dry seasons, 
because the corn grows so much faster, the effect is not so observable. But 
if you fertilize very much you will simply raise a heavier crop of worms. 

There is no fertilizer or substance which can be dropped in the hill of 
corn and destroy the worm or its effect upon the corn — that is, I do not know 
of my own knowledge of such a fertilizer which will kill any insect. We 
have experimented along that line, and have used the super-phosphates- 

118 



saturated with crude petroleum, and muriate of soda, and other prepara- 
tions of petroleum, with the idea that we would get the fertilizing effects 
and the insecticide elTect of the petroleum. But I do not know of anything 
which will destroy insects by application to the crop itself. 



I 19 



CHAPTER Vlll. 

PEA TESTS. 

Ihe |)oa vines ,lurin- ilic years 1899, 1900 and 1901 were severely at- 
tlicted with an insect wliich materially damaged the crop and in some cases 
ruined whole fields. The habits and character of the insect were practically 
unknown to canners and even entomologists were puzzled to account for it. 
The sections first afifected were New Jersey, Delaware and Maryland, and 
a vear later the insect found its way to the western fields of Indiana and 
later into Wisconsin. The canners" in the states first afifected naturally 
turned for aid to their several state agricultural stations and it is to the 
efforts of Professor \V. G. Johnson of Maryland and Professor J. G. Sander- 
son of Delaware that a means has been found for treating the pest. 

The following paper by Professor Sanderson was read at Detroit 
February, 1900, before the convention of eastern and western packers: 

THE DESTRL'CnX'E PEA LOUSE. 

It certainly has been many a year since any branch of the packing busi- 
ness has been so aft'ected by an insect as was the pea industry during the 
season of 1899. From North Carolina to the Bay of Inindy the pea crop, 
hitherto but little annoyed by insect pests, was blighted by the attacks of 
the destructive pea louse. The injury was most complete in Maryland, 
Delaware and adjoining States. In Maryland many hundred acres were a 
total loss, and in general from 50 to 75 per cent, of the crop was destroyed. 
In Delaware about 45 per cent, was lost, while in Xew Jersey the attack 
was not so severe. 

The unusual amount of damage done would be sufficient in itself to call 
attention to this pest, even were it one previously well known, but when 
we find that this species was hitherto absolutely unknown, our interest is at 
onee aroused concerning this insect capable of such sudden and widespread 
devastation. As regards the origin of the pest practically nothing is known. 
For two or three vears ])ast it has done more or less damage to late peas in 
individual localities, but never of considerable imi)ortance. The family of 
plant lice or ajihides. to which this insect belongs, is one Init little known to 
most entomologists, so that the insect mav have been fee<ling on some com- 

1 21 



mon weed for many years without having been noticed. No such species 
has been described from Europe, ahhough it might possibly have been im- 
ported from some other cHme. However that may be, the species was never 
noticed as such until the present year, and has not even yet received a tech- 
nical description. Prof. W. G. Johnson, state entomologist of Maryland, 
has given the insect both its common name and scientific title — Nectarophora 
destructor, Johns — and it is to him that we are indebted for much of our 
information concerning it. 

The damage being done by the pest was first noticed about the middle of 
May, 1899, and from that time until midsummer it became increasingly in- 
jurious. The first case to be noticed involved perhaps the most serious ' 
loss of any. This was on the Susquehanna farm of Mr. C. H. Pearson, a 




well-known A-Iaryland packer, situated upon the Chesapeake bay in St. 
Mary's county, Aiaryland. Here, out of some 600 acres planted, about 500 
acres were almost or entirely a total loss, which in dollars and cents means 
about $30,000. Two hundred acres were at once plowed under to prevent 
the spread of insects upon plants already dying. This and another field of 
100 acres appeared as if swept by fire, so severe was the injurv. The plants 
were fairly incrusted with lice, tlieir whitish cast skins and the sticky honey- 
dew which tliey excrete. 

The lice first attack the terminals of the plant, usually being found in 
the buds and between the unfolding leaves. Later they cover all parts of 
the plant, but feed mostly upon the under sides of the leaves. Thus they 
are always difficult of access by any spray. The mouth parts of a plant 
louse form a long, pointed beak, about one-third the length of the body. 
Inside this beak are several long, slender, sharply pointed bristles. By 



122 



placing the tip of the hcak u];()ii the surface of a leaf and then ■Irivnii; the 
bristles into its tissue, tlie juices of the leaf or stem are secured and pumped 
up into the mouth, and in this way the plant louse sucks the vitality of the 
plant. The injury is, of course, entirely dependent upon the numbers of 
the pest, which, however, owing to the peculiar life history of these insects, 
is usually enormous. Moreover, by attacking the terminal growing portions 
of the plant, the pea louse is especially destructive, and the injury is very 
quickly appreciated. 

The pea louse is about one-eighth of an inch long and of a bright green 
color, identical with that of the ])ea foliage. I'.oth winged and wingless 




forms will commonly be found, the winged forms becoming more numerous 
as the iood supply becomes short. The fore wings expantl somewhat over 
one- fourth of an inch, the beak is bent under the body when not in use, the 
antennae or feelers are long and slender, reaching to the rear of the body, 
and the "tail" — so called — is usually long and pointed. These, in brief, 
are the most striking characteristics. 

As liefore noted, the life history of ])lant lice is a peculiar one, and it 
is to this that their enormous number and consequent destructive ]iower are 
due. As vet the comjilete history of the ])ea louse during the whole year 
has not been observed, neither the egg stage nor the winter habits of the 




pest being known. Inasnuicli as any general methods of cultural control 
must be largely based upon the complete life history of the pest, the im- 
])ortance of ascertaining it is at once apparent. Where the insect passes 
the winter is unknown. Generally plant lice lay eggs in late fall, which 
hatch in early spring, and doubtless this is the case with the pea louse, 
though they have not as yet been discovered. However, as soon as the peas 
are well started the lice are wpou them and commence to multiply. This 
goes on at a marvelous rate, owing to their remarkable i:)ower of repro- 
duction, which takes place without the egg stage, the usual first stage of 
most insects, but by the female giving direct birth to her progeny. 

123 



Throughout the summer all the lice are of this peculiar class of females, 
and only in the fall does a form appear which lays the winter egg. To all 
further growth each louse sheds its skin some three or four times before 
coming full-grown, when it may be either winged or tvingless, but in either 
case soon commences to give birth to young. In the fall I have found that 
about twelve days is required for a louse to become full-grown, and that it 
then gives birth to from twenty to twenty-five young. During late spring 
the time for growth may be only ten days. At any rate, if you will take 
time to calculate the number of progeny from a 'single individual of a 
species which increases at a geometrical ratio of twenty every twelve days, 
you will soon see the reason for the enormous numbers and consequent 
serious damage done by these apparently insignificant insects. 

But from this very fact of such an extraordinary power of increase we 
may expect to find a host of enemies to check the undue multiplication of 
such a prolific insect, for we know that such a condition is very laroely a 




result of the species having so many forms preying upon it that it must 
reproduce extravagantly in order to maintain itself in the struggle for ex- 
istence. Only when for some reason the conditions for the development 
of the enemies of plant lice — such as predaceous and parasitic insects, 
diseases, etc. — are unfavorable, do the plant lice find a chance to increase 
in such numbers as to be excessively injurious. But, now again with a 
superabundance of food, the enemies rapidlv increase, the plant lice com- 
mence to disappear and the balance in nature is again restored. In general 
weather conditions, subtle and but little understood, are responsible both 
for the destruction of the enemies of the plant lice, and often of the lice 
themselves. 

Several insects feed upon the pea louse. Among the most valuable of 
these are the larvae of the pretty, yellow-banded Svrphus flies, which mav 
be seen in large numbers hovering around an infested field, with their 
peculiar rapid flight, darting here and there, while depositing their eggs. 



124 



The vouiii:; which liatch fnnii these arc small maggots, the most common feed- 
mg upon the pea louse bcuig ot a pure pea-green color, while others are 
hrownish and variously colored, and are ahout one-lhird of an inch long. 
As illustrative of the mnnhers in which these occur and the good they may 
do, .Mr. Pearson wrote that during the last few days he packed, his sepa- 
rators sifted out over twenty-five hushels of these "green worms." The 
small ladybird beetles, which as children we were wont to scare away to 
their children in burning houses, and their larvae, also fed almost entirely 
on plant lice, and all of the common species have been found consuming the 
pea louse. Several insects of minor importance also feed predaceously upon 
the pea louse. Usually, plant lice are very largely destroyed by parasitic 
insects, which as larvae live within the plant lice and thus kill them. When 
these become abundant every louse on a plant will sometimes be found 
parasitized. Strangely enough no internal parasites were bred by Prof. 
Johnson from pea lice secured in Mayland, and possibly it may be due to 
this cause that we are to attribute the enormous and unusual number of 
the lice. Late in the fall I found one species (Aphidius Washingtonensis, 
Ashm.) quite commonly infesting the pea lice, here on the experiment 
station grounds (Newark, Del.), and we shall be on the lookout for its 
appearance next year with some interest. 




In addition to the insect enemies of plant lice, they are always peculiarly 
subject to the attacks of several fungous diseases, which spread among 
them very rapidly, and very often destroy large numbers of them in a very 
few days. These fungous diseases are especially prevalent during moist, 
wet weather, but disappear during hot, dry weather of mid-summer. 

Thus Mother Nature has several most potent agencies for reducing the 
numbers of these destructive insects, but unfortunately, when for some 
reason these are diminished, and the lice accordingly become excessively 
abundant, the crop attacked is usually largely destroyed before the enemies 
of the lice again become sufficiently abundant to check their increase. These 
enemies of the lice cannot be artificially encouraged, but by recognizing 
them their destruction may often be averted. 

What, then, can we do with this pea louse, and on the other hand, what 
is he going to do with us? The remedies and the outlook — what of them? 
As already stated, spraying or dusting the vines is impracticable, both on 
account of the closeness with which the crop is ])lanted and the acreage in- 
volved, and because of the impossibility of reaching the lice, hidden as 
they are among the leaves. Fifteen per cent, kerosene is a sure remedy and 

125 



will not injure the plant, but from a careful trial I feel certain that a suffi- 
cient per cent, of the lice could not be killed to warrant its use. And so 
with all other insecticides. 

Did we know the complete life history of the pest we might be able to 
devise some method of destroying it during the winter months, but this is 
a field for future study. 

Fortunately early peas were but little injured last season, while late 
peas were a total failure. For one or two previous years, also, it was the 
late peas on which the lice were noticed. Thus, judging from our past 
experience, we can only rely upon the planting of early varieties for the 
securing of a crop. In general, in Maryland and Delaware, we would ad- 
vise planting no varieties maturing later than June i, and the earlier the 
variety the better. 

As to whether the pea louse will be as destructive during the comino- 




season as during the past, is largely a matter of conjecture. After dying 
out during the late summer the lice appeared again in southern Maryland 
upon the fall crop in large numbers, and were present on a few vines here 
as late as the first of December, after several hard frosts had already oc- 
curred. Such unusual outbreaks of an insect pest generally occur only at 
rare intervals, but often the pest occurs in more than normal numbers for 
a year or two after the outbreak. Thus it is impossible to make any even 
probable predictions for the coming season. It is to be regretted that we 
have been unable to secure a more accurate knowledge of the life of the 
pest, and it is to be hoped that during the coming season we mav secure 
such information concerning its habits as will enable us to devise some 

126 



means of successfully keeping it in conirol. The outlook is not encouraging, 
yet on the other hand it is by no means forbidding. 

PROF. JOHNSON ON TIIK PKA LOUSE. 

The next paper on the program was by Prof. W. G. Joinison, the Mary- 
land state entomologist, whose address also covered "The Destructive Green 
Pea Louse." 

I have to report here one of the most remarkable instances of the sudden 
appearance of an undescribed species of insect over a wide area which has 
ever come to my notice, and which is, perhaps, one of the most unique in 
economic entomology, b'or centuries iiidden in obscurity, a little green 
louse appears suddenly over wide areas, destructively attacking the held 
pea, a plant heretofore practically exempt from the ravages of insect foes. 
My attention was called to it May 18, 1899, by Mr. C. H. Pearson of Balti- 
more city, one of Maryland's largest oyster, fruit and vegetable packers, in 
the following communication : 

"One of my pea fields is entirely covered with a small green louse, which 
is sapping tb.e life out of it, and if anything can be done to prevent it, 1 
want to do it at once."' 

1 made a personal inspection of ^Ir. Pearson's place, containing about 
a thousand acres, locally known as the "Sus([uehanna farm," situated along 
the Chesapeake bay, in St. ]\lary county, at the mouth of the Patuxent river, 
May 24, 25 and 26. Upon my return to my office, the 27th, and after 
a careful consideration of the conditions and facts, I summed up the situ- 
ation in a letter to my friend Dr. L. O. Howard, United States entomologist, 
which I (juotc in part herewith as follows : 

"I have just returned from southern Maryland, where I have been 
making an examination of the outbreak of aphids attacking peas in that 
section. I write this statement knowing that you are interested in anything 
of this kind, and at tlie same time to give you an opportunity to sec with 
your own eyes what 1 have attempted to describe below. The place can be 
reached wiihin a day's ride down the Potomac, and 1 am satisfied that you 
would be well ])ai(l for the visit to see the conditions existing. At the same 
time we would not care to have a public announcement made at the present 
time of this attack, as it might militate against the owner in a wav that 
would be impleasant for him, as his loss is estimated now at between $20,000 
and $25,000. 

"Without a question of doubt, the destruction caused by this insect is 
the most complete I have ever experienced. It is certainly a sad sight to 
look over a lOO-acre field of peas and see them literally incrusted and cov- 
ered with this insect. There is no hope to save even a fractional part of 
a crop in this field. Tt is one of desolation. As far as one can see the 
plants are shriveled, withered, and in many instances the leaves are blackish 
looking, as if a fire had gone over the surface of the ground, scorching them. 
The whitish cast skins of the insects, stuck to the drooping leaves in the 
honev-dew. which had been excreted by the insects evervwhcre over the 

1 27 



entire field, gives one the impression tnat a terrible plague has sureh- visited 
that section. The attack is not confined to this particular loo acres, but is 
present in adjoining fields. The owner of this estate has planted this season 
1, 800 bushels of peas, besides using with them 130 tons of commercial 
fertilizers, covering an area of 600 acres of land in all. 

"To say that the condition is discouraging to the owner is not necessary, 
in view of the fact that at present we are helpless, so far as a practical 
remedy is concerned. It is safe to say that if the present weather conditions 
prevail very much long-er a total destruction of at least 200 acres will be 
the result. In fact, it appears to me, after a careful examination of the 
place, that the greater portion of the 600 acres is doomed to destruction 
within a few days, unless nature comes to our relief in the meantniie. At 
the time of my visit yesterday the insects were flying over the field, already 
dead, in such swarms that it was rather uncomfortable to walk or ride 
through them. 

"The attack, however, does not seem to be confined to that one particular 
region, as a correspondent from a Virginia county (Westmoreland County, 
Mount Hague), writes the Baltimore Sun that he has lost an entire field, 
sending specimens, since referred to me, which I find to be the same species. 
A careful and close examination of the peas in this neighborhood shows that 
they have been infested, though not to the same extent. 

"This condition is certainly unfortunate for the people, mostly colored, 
of that section, as many of them are dependent upon the pea crop for em- 
ployment, there being on the Susquehanna farm a large cannery, fully 
equipped with new machinery, boxes and a million tin cans ready to have 
utilized this crop of peas." 

Briefly stated, this was my first introduction to the new pea pest. Fur- 
ther investigation showed that it was widely distributed over the State, and 
that serious injury would surely result to the large acreage of peas planted. 
The growing of peas in Maryland is a very important industry, and reliable 
conservative authorities have placed the loss the past season at $3,000,000, 
the principal cause being the destructive green pea louse. In many cases 
the destrtiction was complete, varying from mere garden patches to hiui- 
dreds of acres. The final outcome of the crop where I made my first obser- 
vations was fully as disastrous as we predicted. Four-fifths of the entire 
crop was a total loss ; in other words, 480 acres out of 600 were literally 
sucked to death. In another instance only no out of 500 acres, belonging 
to the Louis McMurray Packing Company, of Frederick County, were con- 
sidered worth ctitting. It is useless for me to enumerate in detail all the 
places I have upon my notes where the peas were not cut at all. Suffice 
it to say that pea growers everywhere along the Atlantic coast consider 
that they have been visited by a veritable scourge. The attack has not been 
confined to Maryland alone, but I have records of its occurrence in Dela- 
ware, New Jersey, New York (Long Island), Pennsylvania, Virginia, North 

128 



Carolina and recently from Connecticut, Nerniont. Maine, Uliio, Canada 
and Xova Scotia. 

Talkin.q- with some of our lari^est i^rowers, 1 find the pest was present 
last season* in considerable numl)ers in certain fields, and some laborers 
(colored) even refused to pick peas from the infested areas. I am in- 
formed that it was present upon late peas on the Xew Jersey experiment 
station grounds the fall of 1898. 

The species responsible for this condition of affairs properly belongs to 
the old genus Siphonophora, but as this name is i)rcoccu])ied in the Myria- 
poda. and is also used to denote an order of oceanic 1 lydozoa I think it emi- 
nently proper for us to recognize Mr. Oestland's name, Xectarophora, for 
this genus. Specimens of the insects were submitted, through Dr. Howard, 
to the well-known authority on the Aphidae, Mr. Theodore Pergande, who 
considers it an undescribed species. Inasmuch as Mr. rergande docs not 
care to describe it, it is my privilege to name the insect, and I have called 
it Xectarophora Destructor, giving my description in the b'ebruary number 
of the Canadian Entomologist. 

The insects attack the young vines, clustering usually at first under and 
within the terminals. When the leaves become overstocked the lice cluster 
upon the stems, quickly sapping the life out of them. It was not an uncom- 
mon sight to see a vine literally covered with lice; indeed, whole fields of 
a hundred acres, as noted above. Besides the field and garden pea, we have 
found tlie same species on sweet peas vetch, and have ke])t it for some time 
ui>on clover. In my opinion some common plant is its natural food, but as 
yet I have been unable to detect it. 

There is little opportunity for work upon this insect from the experi- 
mental standpoint, as it is practically impossible to spray a field of peas 
when they are growin.g for commercial purposes. They arc drilled in like 
wheat and completely cover the ground. \\\- have shown, however, that 
kerosene and water can be used to good advantage upon small patches. We 
used kerosene from 15 to 30 per cent, solution in the Deming sprayer with- 
out injuring the vines. It is not desirable to use a stronger solution tlian 
15 i)er cent., but the vines will not be injured by a stronger .solution. The 
latter part of June we used whale-oil soap very successfully upon late peas, 
at the rate of i jwund of Good's potash-lye soap in 4 to 5 gallons of water. 
Some of our large growers used tobacco dust and air-slaked lime, swung 
broadcast, when the dew was on, over the vines. It was verv satisfactorv, 
but hardly warranted the expense and trouble. It is exccedinglv difficult 
to reach these insects with either a spray or dust. With our i^resent knowl- 
edge of the creature, we must (le])end largely upon natural resources for 
checking the multiplication of certain sjiecics. I paid particular attention 
to those in.sects and diseases that destroy plant life. Even at the time of 
my first investigation on Mr. Pearson's jilace ('Mav 24-26) there were 
enough syrphus-lly larvae j^resent for me to predict the destruction of most 

129 



of the lice by them, if weather conditions did not intervene to bring about 
that desired condition, before the end of the season. 

I have observed three important groups of insects feeding upon the pea 
louse; first, and most important, the syrphus flies (sdfe Nos. 2 and 3) ; sec- 
ond, the lady beetles, and third, the lace-winged flies. While all of these 
were found in every field examined, it was interesting to note the pre- 
domination of certain species in different localities. For instance, the 
syrphus-fly larvae were most numerous in the southern part and eastern 
shore of the State, while the lady beetles abounded in central, northern and 
western Maryland. 

The real importance of the syrphus-fly larvae in the reduction of the 
species was shown beautifully in southern Maryland where they were so 
abundant the first and second weeks in June as to almost completely destroy 
the lice. Their presence, however, did not save the crop of peas this sea- 
son, but what their almost innumerable number means for the future is hard 
to predict, and furnishes a subject for future thought and investigation. 
I am now going to quote a paragraph bearing on this topic from a letter 
from Mr. Pearson, dated June 12th, which reads like a fairy tale, but is 
nevertheless an undisputable fact, coming as it does from a man of un- 
doubted veracity. He says : 

"The insects (lice) started to disappear last week, and are now about 
all gone, but too late to be of any advantage to me this season. The last 
few days I packed the separators sieved out about 25 bushels of green 
worms, which no doubt proves that they destroyed the lice." 

The "green worms" referred to were the young of the syrphus flies 
(see No. 2). In this connection I might state that I have bred three species 
of syrphus flies from larvae found feeding upon the pea louse. The oblique 
syrphus was by far the most common and important species. The greater 
bulk of the 25 bushels mentioned by Mr. Pearson consisted of this species. 
It was common all over Maryland, and was bred by me also from larvae 
feeding on lice sent to me from Virginia and Connecticut. The larva 
is pea green in general color, slightly streaked with white, varying in length 
from a quarter of an inch to a third of an inch when full grown. It pupates 
upon the leaves or stems of the peas, or upon some other object near by, 
rarely going to the ground. We have them upon corn leaves, near infested 
pea fields. The American syrphus was usually found associated with the 
preceding species, but not so abundant. The larva is larger than that of 
the obHque syrphus, brownish in color, somewhat mottled and larger. It 
also pupates upon the plant or even below the surface of the ground. The 
adult is also much larger than oblique, and can be distinguished from that 
species, even when on wing, by its bee-like hum. The remaining species, 
the cylindrical syrphus, was not common, but was found in two localities- 
associated with the others, and is much smaller than either. Of the ladv 
beetles four species were observed feeding upon the lice in the fields. Both 
adults and larvae were everywhere present in the infested fields. At the- 

130 



time ot ni}- visit, Juno 30th, to the infested areas of l"'ro(lerick County, 1 
found pupae of tlieir insects attached to leaves of peas, weeds, grass and 
corn — in fact most anytliing- where the larvae could secure a hold. Some- 
times three or four were found upon a single leaf. The lice were on the 
decrease, and it was clearly seen that the lady beetles and other predaceous 
insects present would soon devour those remaining. The larvae and eggs 
of the lace-winged fly were found throughout the infested districts of the 
State, and it has been an important factor in the reduction of the lice. The 
soldier beetle (see No. 3) was also observed by me feeding upon the lice in 
my garden near the college. This completes the list of predaceous insects 
observed and bred. 

I was surprised, however, in not rearing any hymenopterous parasites 
from these lice. None appeared in any of our breeding cages, and not 
one was observed in the field. Dr. James Fletcher, the Dominion F,nto- 
mologist of Canada, and Prof. E. Dwight Sanderson, of Delaware, inform 
me they have bred some parasites from this pest. 

On the i8th of June I noticed a number of dead lice adhering to pea 
leaves in my garden, and inferred that death was due to fungous disease. 
The disease continued to increase until about the 25th of June, and finally 
disappeared. Sometimes ten or twelve dead lice, in all stages of develop- 
ment, were found upon a single pea leaf. Specimens were preserved, and 
will be reported later by my colleague, Dr. C. O. Townsend, our State path- 
ologist. 

As noted above, I saw the first specimen of this insect in Alav, and I have 
had it constantly under observation ever since. We have some very in- 
teresting facts. In the first place we have found no male, but plenty of 
females, attending strictly to business, producing living young. It is not 
an uncommon thing to find a female walking around over a leaf with a 
young one projecting from her body. They obtain their food by inserting 
their lance-like beak into the tissues of the plant. 

W^e have a colony of lice now upon peas in our laboratory, where they 
are breeding at this time. That the lice can stand a considerable amount of 
cold, even freeze, and still revive and produce young was abundantly proven 
by us this winter. The colony in our laboratory froze up Dec. 23d. There 
was ice half an inch thick in a jar. We thought surely we had lost our 
"treasures," but to our surprise a few days later, as the weather moderated 
and the room warmed up, we found them as active as ever. I had speci- 
mens sent to me from New Jersey at mv request, from Mr. A. Blakeley, 
taken from the field late in December. i\ir. F. C. Chittenden, of the U. S. 
Department of Agriculture, tells me he saw a colony breeding on the agri- 
cultural department grounds in Washington on vetch, Jan. 27th. With 
all these facts before us, it seems very probable that the pest passes the 
winter as a perfect insect, breeding all winter when weather conditions are 
favorable. 

As to the future, T confess it is hard to predict what the spring will bring 

131 



bring forth. There may be a repetition of last year's devastation, but I do 
not look for it. I cannot help believing nature will do her part in relieving 
the grower and packer of this terrible scourge. 

Let us ask ourselves a few questions ! In the first place, what has be- 
come of the untold millions of syrphus flies, lady beetles, lace-winged flies, 
soldier beetles, hymenopterous parasites, etc. ? 

I cannot believe they have been destroyed, and I reasonably look for- 
ward to spring when they will come out of their hiding places, hungry 
and ready to pounce upon the first louse that makes its appearance. If 
this holds true, then the louse will have a hard time to establish itself again, 
in such destructive numbers over the wide area named above. 

As a final statement, I would say, in my opinion, it will be wise to plant 
peas this season earlier than usual. Even if the louse does appear in de- 
structive numbers, the very early crop will have a much better chance for 
maturity. In Maryland I have advised some growers to plant in February. 

I have been asked many times if I would plant if I was a grower? I 
certainly would ! I would take my chance largely on the early crop, as one 
year's experience has shown us that the later peas, save a few instances, 
were almost totally destroyed. 

We must speculate a little, for we have no past history of this species to 
deduct conclusions or make generalized statements from its previous habits 
and behavior. We have but one year's experience, a sad one for many a 
grower, behind us. Nature has done her work well, and there is nothing 
left for the economic entomologist to do other than to acknowledge his 
inability to cope with such mysterious forces, and keep plodding along in 
the darkness, hoping to get a ray of light here and there as he unravels some 
hidden truth. 

Does it not seem that old Mother Nature is resenting the progress of 
civilization? She is calling a halt; but man, in his eagerness to gain a 
livelihood, is forging ahead blindly, apparently not heeding these warnings 
that he is going too fast. 



132 



CHAPTER IX. 

Prof. W. Cl. jolmson of the Maryland Agricullural College, was one 
of the principal speakers at the Annual Convention held at Rochester in 
February, 1901. His lecture, being on the Green Pea Fly, was especially 
interesting to the canners of peas who were still battling with this dreaded 
insect. 

The Professor spoke as follows : 

1 am to speak to you of the ravages of the Green Pea Fl\, some- 
times known as the Green Pea Louse. I will give you the reason 
for changing the names : This has been known from the beginning 
as Green Pea Louse and there has been fault found with that name 
and it has been thought best and wisest in the present circumstances to 
change the name in such a way that this insect which has become so noto- 
riously established in the pea growing sections will not be connected with 
the pea ; in other words, not connect this insect with the vegetable, and wc 
have thought best to change the name Pea Fly to Green Fly, eliminating 
the name Pea entirely ; and I think the name Green Fly should be referred 
to in our journals and then the popular mind and those consuming the veg- 
etables, green peas, etc., will have no unpleasant connection with this insect. 
The term louse is rather repulsive when you stop to think of it, and that is 
objectionable on the face of it. Many persons reading of this insect would 
have reason to believe that in some way, if it is so abundant in the field as 
reports sent out would indicate, they might get a good percentage of them 
in the cans and in the canned goods themselves, and in that way no doubt 
the popular mind would be prejudiced. In the same way the word Pea 
Fly is objectionable. The popular public would just as soon eat a louse as 
a fly and you have got to eliminate the name Pea. If we refer to it only as 
Green Fly every one will know what we mean and the general puljlic will 
not be alarmed in looking for Green Pea Fly or Louse. 

I do not think this morning it is necessary to go into the history of this 
pest. I take it for granted most who are here this morning will be here this 
evening and at the Clam Pake we will introduce a part of the talk I had 
planned to give you, not in a stated lecture but throwing out in another 
way and using the stereopticon, and perhaps answering questions. This 
morning I would prefer to have questions asked direct and ] will answer 

133 



them to my ability and that may perhaps bring out what will not be brought 
out to-night. There have been many questions propounded to me and I 
have declined to answer the individual, knowing they would be of interest 
to others, something about the general distribution 'of the pest. That is 
interesting to the canners and those interested in the canning business — 
where this pest has not yet been seen or not detrimental to the crops. Sev- 
eral gentlemen have stated to me that they have not seen the insect in cer- 
tain parts of New York ; at the same time I have had data stating to me that 
that green fly or the green creature we are talking about, is already estab- 
lished in Central New York. It was only seen in the late season and it 
was in the latter part of November when we heard of it in Cayuga Lake 
section and Seneca and Central New York. At the same time the inquiry 
comes to me whether it has reached up to Maine. We know it has. We 
have records of it late this fall on late peas in Maine and through other sec- 
tions where we least expected to find it — all through the New England 
States — I can't name an exception where that pest has not attacked the late 
peas, or complaints coming from those who have attempted to grow the 
sweet pea for ornamental purposes. 

You all know the reports that have come to us from the northwest, in 
the Wisconsin section, and we have records of its occurrence in Nova Scotia 
and in Canada. Late this fall a friend of mine in Canada writes me that 
late peas for ornamental purposes were quite affected this season. 

It is verv hard for us to deduce any general conclusions so we might 
make some statement concerning the future. It would not be wise from a sci- 
entific or business standpoint to predict the future or even venture a tradi- 
tion which you might use as being conclusive for the coming season. I say it 
is practically impossible — for the history of this insect, you know, is only a 
recent .one; it has only made two years' history. May i8th, two years ago, 
was the first occurrence, the first general record of note we had of this 
insect. Since May i8th two years ago that insect has been under observa- 
tion up to the present time. I have the insect breeding in my laboratory 
now on peas and cow peas. I have the progeny of various generations 
which we have cared for through successive stages of this same green fly 
by way of getting at its life history. Those points are very well worked 
out but there are many facts that need working out as yet, especially with 
reference to the natural agencies which produce it, and study this insect 
with a possibility of elimination, for a time at least in the future, with the 
prevailing conditions which might have preceded it. We know as matter of 
fact that this insect was exceedingly abundant late last fall — enough oT 
them, so we would say, left for seed. Some of you are familiar with the 
rapidity with which this insect propagates and with only a few left it is only 
a matter of a short time before you have a large progeny. In this group 
of insects we have the peculiar feature of the insect mother bringing forth 
living voung. This is not an exceptionally peculiar case because we have 
some other insects which bring forth living young instead of eggs, but in 

134 



this case we have the insect mother bringing forth Hving young which soon 
mature and multiply with great rapidity. The young taken from the body 
of the mother on March 4th was carefully watched in a cylinder and eleven 
days later had reached maturity and was reproducing, lived forty-five days 
and during that period was the mother of 145 individual flies. You 
can recognize that that insect was a grandmother many times over be- 
fore the last was born in that period of forty-five days. You take a little 
insect not larger than a pin's head and place it upon a plant a man would 
look at the insect alone and say it was not possible, of such a character and 
size to be of great menace to him as a farmer or as a canner, that would be 
his general conclusion if he saw the insect; but what it lacks in size it makes 
up in number. It is not the attack of a single individual but of the enormous 
aggregate you get in a few weeks. The history of this pest is being care- 
fully worked out and we know practically all the details from early spring 
through the summer and through the winter. I am watching it carefully 
now, not only in the laboratory but in the field. It is still in the field in 
clover patches near Washington and in the south and still breeding and 
we will find it there this month breeding on one of the plants whicli this 
insect feeds upon. We saw it last January breed in the open field in the 
agricultural grounds; we saw it as late as December this year breeding in 
the open field. I saw it also in December in a southwestern state breeding 
in clover in the open field. There is still doubt as to the ])lace of wintering 
of this insect in the extreme northwest. This is a statement many would 
doubt, but it is true that we have seen this insect frozen solid, thawed out 
and begin reproduction shortly after. We saw this a year ago ; I was 
quarantined on account of sickness in my family, the pipes were frozen and 
unbeknown to the janitor all my plants and delicate little creatures were 
frozen in my laboratory. \\'hen I was released and went to the ofiice I 
found not only the plants were frozen in the ground but the little creatures 
were frozen as stiff as icicles, and it occurred to me that although these 
little fellows were frozen they might thaw out and I could still save my 
seed. With a pair of forceps I took these little green flies, carefully, by the 
legs — because they will break ofT as easily as the finest spun glass — and 
although they were frozen, eight days from the time of that transfer they 
were producing, and that whole colony still goes on. It is not an uncom- 
mon thing for us to freeze insects solid and take them out and still have life 
though frozen. That is true of the notorious chinch bug ; and that is known 
because this enters into the canning business, to those that grow sweet corn. 
Up in this section the chinch bug is another creature; we do not find it in 
the corn but in another place. The chinch bug has been known in several 
cases to be frozen solid in cakes of ice and then thaw out ; it is not an ex- 
ception to have these frozen solid and then recuperate and begin reproduc- 
tion a short time after. 

Some one advanced a theory yesterday that perhaps the cold weather of 
the northwest would freeze these insects out, but not long ago I had a talk 

135 



with the ex-governor of Wisconsin and he told me there was a time last 
winter when the thermometer was 46 degrees below zero, and we would 
therefore say that the cold winter would have no imme^diate effect upon- them. 
The closer and colder the winter the better the effect upon insects as a rule. 
It is a fact the insects that live over winter in a dull state will find a secluded 
spot and live until open spring but if it is an open or rather warm winter 
and vou have places where the sunshine is quite warm, in an exposed place, 
these insects will awake or come to life and go where the sun shines and 
then the cold will come and strike them and freeze them before they can 
get back, so that an open winter is as a rule more detrimental to the insect 
as a whole than a close, cold winter. The average farmer or person would 
think the reverse and would think the colder the winter the least prospect 
of an invasion of insects the following year. 

So much for these facts. There are many other points I might bring 
out this morning but, as I stated in the outset, I believe at this hour it would 
be better for you to ask the questions. 

(Some one said he would like to ask about the chinch-bugs.) 

I would like first to confine this to the subject of the green fiy and then 
take up some other subject. 

Question : I would like to ask the professor if it is not possible for these 
insects to live through winter in the form of eggs? 

Yes, there are many species that do live as eggs. Many familiar with 
fruit trees have seen a little green fly — or in this instance we can say green 
louse — around apples and the ladies will be familiar with the little green 
louse around rose trees. In the instance of the one on the apple you will 
find around the twig or about the bud a lot of little black eggs and sometimes 
covering the entire bud. In that condition those eggs remain there until 
spring; no degree of cold up to this time has been known to affect them. 
On the other hand, there has never been an egg seen of this pea iiy or green 
fiy ; at the same time it is a question whether the opposite sex even exists. 
This is a case which we know is reproduction without a male. It is a 
very singular thing in nature, but at the same time up until very late 
fall the male of this creature has never been seen, and to prove that repro- 
duction is possible without tiie opposite sex with the creature I mentioned 
a moment ago in generation after generation — the little creature 
from the time it was born taken and put on that isolated 
pea and the first born from that creature taking place at the expiration 
of eleven days, and one taken from that and in case of reproduction taking 
place at the proper time. I will say I have found recently in the colony in 
my laboratory, on cow peas, I have found one male, another professor has 
found two, but it is still a question whether that is the opposite sex of this 
same individual, but it is one of those peculiar things in nature that we must 
know all the facts about and study from that standpoint. The practical 
solution of this whole thing may hinge on establishing the fact that an 
opposite sex does exist. We know as a matter of fact that in many cases of 

136 



plant lice, of which this is one species, the early part of the season we have 
this organic reproduction, no male from spring tnitil late fall, and the female 
at the last of the season producing an egg, each individual producing a single 
egg, that egg remaining throughout the winter and hatching in the spring 
and producing what is known as the stem-mother, but no male appearing 
again until late fall. This is a very peculiar freak in nature and the same 
thing may be the fact with this insect. Up to the present time we in- 
fer it is strictly an orgijuic form with the possible exception 
which I have named : We have found the male on the cow pea and 
that may have been produced by some abnormal condition. I do not think 
the cow pea will ever enter as a factor ; however, I have had them breeding 
on it in my laboratory, while generation after generation have disapjuarcd 
on the ordinarv pea. I have some facts which I will give you to-night, 
from the time the pea appears through the ground. Take a single pea i)lant 
and put upon it a young insect from the body of the mother, immediately 
after birth, and then calculate the time from the time of birth until that 
plant is destroyed by its own production. We have also discovered that 
that plant will succumb no matter how much water you can give it. Some 
one has asked the c|uestion. if we have plenty of rain, would not these 
plants overcome it? No doubt they would; of course, the stronger the plant 
the more it would resist, the same as with a human being; a strong, vigorous 
being might be in this room with a malignant disease and not suffer con- 
tamination. The same thing holds true in the plant world ; and we have 
given them all the water and still at the expiration of a period that i)lant 
would simply begin to collapse, droop, grow yellow and die, which many 
of you have seen in the open field. I say these are facts we have to deter- 
mine experimentally ; but the mere fact of plenty of w-ater and the attack 
of this insect will not save the plant ; it has not solved the question ; there 
are other conditions we have to consider. With damp, warm rain, which 
makes it possible that the green fly be carried away the question of fungous 
disease arises. 

Question : Docs it appear in the same place the succeeding vear and the 
same form? 

I would say yes and no. The local features determine that largely. In 
one instance an insect appeared on a farm, and it occurred the succeeding 
year in great numbers, but at the same time not as abundantly as the year 
previous. In another case on the southeastern shore, Maryland, two years 
ago it was exceedingly disastrous in a given held, while this year it was com- 
paratively unknown. < )n the other hand, where it was abundant two years 
ago it was still more so this, in other cases where it occurred two "years ago 
there \vere none, this year it was abundant. So there is no rule you can 
give in a given locality by judging of what occurred the year previous. We 
are still in the dark. Nobody knows or dare venture to predict what we are 
going to have next year. As an illustration, in 1899, it completely riddled 
a whole field while in 1900 it wasn't seen. I can name case after case in a 

137 



dozen States of similar character. I know one case where we would almost 
have ventured a repetition in a field where there were French canners, a field 
of peas belonging to Mr. Roe, a member, of Maryland, and at the time we 
saw them we would have predicted there would not be a can harvested from 
them, judging by the life in each bud, but a little later a great rain came 
and those dead insects were plastered and stuck all over those green peas. 
This year the best peas were taken from that section. 

Question : Would a violent rain storm and almost a cyclone account for 
their disappearance? 

Well, that would to my mind explain their disappearance largely, but 
at the same time there are other cases where the reverse is the rule, so no 
rule can be laid down until we have history back of us. After we have 
studied the thing ten years perhaps we can. I did venture to predict, early 
this spring they would see it in the northwest. I felt certain they would 
from the mere fact that they had them in Canada, and I felt almost certain 
that they would appear in the Lake Michigan region and that prediction 
held true, but I say that was not from any facts in hand that would war- 
rant it, but the conditions were such that we felt warranted in makmg that 
prediction. You all know the outcome from the northwest this season. I 
do not think I will be violating confidence when I tell you that I have been 
told since I came to this convention that one individual lost eleven hundred 
acres in the northwest this season ; I know another instance where five hun- 
dred acres was a total loss, and from that down to the little garden patch 
or the sweet peas in the garden of some of my acquaintances, and in most 
cases the cause of the death was not known to the individual until the 
whole question came up of the green fly on peas. 

Question : I was going to ask you if you thought where there was an 
abundance of clover near, whether it would be a benefit or serve as a pasture 
for the fly? 

It would be a benefit to the fly but not to the growers. I know some 
growers have been accustomed to growing clover with the peas and I would 
discourage it for this reason : we know the insect does live on clover 
and it likes clover and there is no doubt in my mind that is the original plant. 
In one of our counties in the southern states sixty-four acres of clover 
were destroyed by this fly so it was not even used for hay. There is no 
doubt in my mind that we must consider clover in the question. 

The first record we had this season was from Mr. Roe, the 28th of April, 
and practically the same hour a letter was received from another gentlemen 
that this insect had ruined forty acres of clover in a county in the southern 
part of the State so they had been in that clover for many weeks, but that 
was the first Mr. Roe had seen it on his peas. The owner was attracted 
by the yellow condition of the clover and saw these green insects but he 
did not know what they were and sent a package to me. You see those 
insects must have been working there from the opening of spring up to the 
first of May, practically, and after they had cleaned out the clover if there 

138 



had been fields of peas just a few inches in height the whole colony would 
have attacked them. We have in the female form both the winged and 
wingless forms to care for the species ; the wingless which must either 
be carried by the ant or plant and the winged. Where it is necessary to 
carry one insect by another, the ant usually carries. We will have some- 
thing to say about that to-night. This will bring up the subject of lice on 
corn which this year has been on sweet corn. The root louse of the sweet 
corn, I will take up later. 

I would say, be cautious about plantmg clover, especially in pea fields. 
There are two reasons, I do not believe it is good practice ; clover is a legume, 
gathering nitrogen and storing on the nodules, and pea is a legume. You 
have two crops of the same general character and you must avoid that : it 
will not do to have clover and then peas, year after year, but you have got 
to bear in mind that that soil has got to have a certain amount of proper 
fertilizer. I do not believe, on the whole, that planting clover in pea fields, 
letting one succeed the other constantly, is good practice. It is necessary 
in some cases to follow that course. It would be best to hold ofT a year and 
then put your crop down and perhaps work it the first year in corn, if you 
saw fit, and then peas or some other crop which would be best suited for 
your rotation. I would be a little fearful, on large areas, in having one 
legume succeed another. I have known of some instances where peas have 
been on one territory for five seasons. That may hold, if that land is prop- 
erly taken care of — like taking care of a man or feeding a horse — if you 
give the land the proper food, at the right time, that soil will increase or you 
can hnld it at a given level. I can cite to you one instance back in an Eng- 
land experimental station, where they have grown wheat on the same land for 
forty or more years and they have not diminished the yield per acre. It is 
simplv the vegetable i)lant food that soil needs. 

Mr. Roe telegraphed us, as I said before, on the 28th of April, and a few 
days later ]\Ir. Scott and myself w^ere at Mr. Roe's place. I was satisfied 
that there was a clover field in the immediate neighborhood, where we would 
find these insects, and like a pack of hounds after the fox we looked, and 
we passed almost opposite corner, diagonally across, without finding the 
green tly. and then on almost a quarter of acre of clover we found some- 
thing wrong with the clover. The plants were withering, looked as if they 
had been sprinkled with something ; there we found the fly and we found 
the same disease in that clover we have been speaking about, prevailing. 
The bunches of clover were rather moist, a good deal of moisture at that 
time, and we found this same disease prevailing. We traced it back to a 
given locality, and in most instances that could be done. In other cases 
I know of pea fields set out in spots where there wasn't a clover field for 
miles around, that were badly afifected. Where they came from — I will use 
an expression I heard this morning — the Lord only knows ; where they 
came from I don't. There wasn't a clover near, and there were woods on 
either side: and 1 think we will find, when ferreted out. there are many 
plants on which it will feed. 

139 



Question : The question I was going to ask was not so much the rotat- 
ing of clover, but I think our State (Wisconsin) is considered quite a clover 
State and much more so than other States where the fly has done so much 
damage and I wondered if where the clover were grotvn the pea would be 
so much damaged. We have a great deal of clover and grow considerable 
of peas and so far we haven't been bothered by it. 

Mr. Johnston : Sometimes, like taking a dose of strychnine, a little bit 
is all right and a little too much is too much. You can use so much with 
a certain degree of safety ; and in the same way I would apply this princi- 
ple to clover: If your section is a great clover area and your clover is 
greater in extent than the pea industry I would say they might concentrate 
their attack on a given area. You know as a matter of fact they do distribute 
themselves very rapidly. On the 28th of April when at Mr. Roe's place you 
could just occasionally find an old female around on that forty-eight acre 
field, you had to hunt a great deal ; a week later they were more abundant ; 
a week later they were still more abundant, and about a week later there 
was scarcly anything left. 

Question: The Clinton Canning Company of Rome informed me not 
long ago that some one connected with Hamilton College was studying the 
pea louse and found the egg; and it may be in the north they lay eggs and 
in the south they do not. 

Prof. Johnson : That may be true. 

Question, continuing : I wrote to our professor about it and asked him 
if he would not ascertain the facts. 

Mr. Johnston : There is a possibility that it may be found. A man 
might find an egg now, which we very often do, and dare not make the as- 
sertion that it was that of the green fly because it might prove to be a differ- 
ent species, that is, a species closely allied to it. It is conceded that this 
insect is closely allied to one that has been known for a hundred years, or 
more than a hundred years, in England, known there as green dog — attack- 
ing clover ; but the specific differences are so minute that they must of course 
be handled under a microscope. There is no doubt there have been similar 
insects working in England for a hundred years or longer : Just why this 
insect should appear here just now and not before is an interesting question. 
You have all been growing peas for years, but two years ago was the first 
that this insect was considered from a commercial point of view, but it is 
a commercial factor now. 

Two years ago I was called into Washington County of our State to in- 
vestigate the question of the armv worm invading a millet field. I first 
scooped up many worms two or three inches long and examined them to 
see if there had been deposited an egg of a house flv, which is parasitic, on 
their back ; if I could find that egg the worm would not mature. I found 
that 80 per cent, of the army worms in that section were parasitized of that 
insect. There are only 13 per cent, to reach maturity and the chances are 
that only 2 per cent, would reach maturitv. With 2 per cent, it would take 
perhaps five years, from that 2 per cent, that is left, before they would be in 

140 



destructive numbers. All wc ilid was to make some mechanical appliance 
to handle them, and we simi)ly left them there — you could scoop them up 
bv bushel basketful and we simply permitted them to remain there and the 
natural i)arasite matured and destroyed their perceritas;e and as a mailer of 
fact that insect has not been seen in that locality since. 

In 1895, when I was located in the Champlain district, the army worm 
was not so much affected by the parasitic insect, but the fungous disease at- 
tacked them very much — which I will speak of to-night— how, while they 
were feeding on millet stalk they would be taken sick and would die before 
night. There were so many of those dead worms hanging and dangling 
to the timothy that they could not use il. That disease always attacks the 
army worm at the rear end of the creature, and it was not an uncommon 
sight to see an army worm living and feeding while the hinder part was 
deca\ed with disease. There was a field where nature was doing her work. 
Here is another hold where a man finds it in his field and says I will not 
attack that. I will lean on the Lord. Just as sure as you do that you may 
rest assured you are going to wait a long time before the Lord is going 
to get around to help you, you have got to do your part. When you come 
to this pea fiv it is a serious question and you have got to fight it. Yoai 
have got to fight il as mechanics. 'J'liis fellow has not a weak point any 
place, at least I have not found a vulnerable point and you have got to get 
Mr. Scott and others to work it out from a mechanical standi)oint. I be- 
lieve this will be solved from such standpoint. Most of the trade I think 
knows it ; this little creature you can hardly see during the two years has 
been the instrument of destroying seven million dollars" worth of peas. 

I don't care whether you are growing green peas or making tin plate or 
whether you are manufacturing machinery or fertilizer, this question re- 
solves itself down to one of economics. It is not the man who is studying 
the little green fiy but the one who is studying the whole industry. There 
are eighty-eight industries afTected by ihis little green creature. Every 
industry rejiresented in this conveiuion is more or less interested in this 
question ; and that is what 1 am here for : I am here to answer those questions. 
If I don't 1-now I will say so. 

Question: You spoke al-/Out these insects traveling. If they get started 
in one direction do they continue in that direction or do they branch off? 

1 cannot answer that definilel\-, but there is no doubt in my mind, on 
account of the delicacy of the wings of this insect, they will go with the 
prevailing wind. If you are in a section where there is what is known as 
prevailing wind. 1 would say ihey would go largely in that direction. I 
did see them in one case where they a])peared in such great swarms it was 
uncomfortable to drive through them. That is where a field of about 260 
acres was just at the jioint where there was no longer any juice left in the 
old plants for the green pea fiy to suck and so each one that had wings took 
wing and the whole atmosphere was filled with them so it was uncomfort- 
able to drive through them. That holds true with other insects. In the 
chinch-bug section when there is nothing left for them to feed upon, they are 

141 



^oing to get out and go where they can find the best feed and get it. On 
the other hand, that is about the only time the chinch-bug uses his wing. 
Some, you know, haven't wings, but they get there all the same, and it is 
only a question of nature, if they want food they will take flight. And 
insects will take flight in the spring to find a breeding place, a field of rye, 
etc. The same with the pea fly — I have only seen them on wing when they 
want to feed. I do not blame them for sucking a nice, juicy pea instead 
of a dry clover stalk; I would do the same thing myself. A nice, juicy 
variety will perhaps suffer more than some other. 

Mr. Goldmark: You mentioned a little while ago this insect had been 
known in England for a hundred years. Was it ever known to exist in 
France, where there is a large pea district? 

We can only go by history or record. That certain records of it both 
in France and England have been deposited from time to time. We infer 
that it was the same creature or similar in character. It has occurred in 
literature along that line. There is no history back of it. We are working 
in the dark. There is no important record. Another point we have: In 
some of our local press notices twelve or fourteen years ago records of in- 
vasion of crimson clover fields along the Potomac river by some insects of 
similar character; that is, the plants were killed or injured very seriously. 
We infer it was the same creature. While we haven't the specimens and 
no way of getting at it, there is no doubt in my mind it was the same identi- 
cal chap we are discussing to-day. 

Question : Did I understand you to say there was no solution found to 
destroy this insect in the way of spraying? 

Yes, there are solutions found that will destroy it when you can strike 
it. You know it goes in the terminal buds, the breeding females will go 
inside and start their colony there and it is almost impossible to get at the 
insects within that fold ; you can spray or you can dip that bud right down 
into the solution and it will form a iDubble around it and that will burst 
wlien taken out and the little fellows will be all right in that bud. Some 
spray. We did this season. Mr. Pearson, the Baltimore packer, perhaps 
did more than any other one in America. He got ready for it, and Ave all 
know his heroic fight this year, and it seems to me Mr. Pearson gave it a 
thorough, practical test and from the standpoint of spray, up to this time 
we have had nothing that would do the work. From 5 to 20 per cent, would 
always be left irrespective of the area and manner in which you applied 
the spray. That is a pretty large factor, because it is only a few days before 
they will breed and you will have to go all over that again. It resolves 
itself down into a question of mechanics, as I said a moment ago, brush. 
You know very early varieties planted early have sufl:'ered less from these 
insects than those planted late. I understand there is to be a large number 
of acres of early varieties planted early. With the planting of so many 
early peas and planting them early, what is going to be the efifect? Another 
year will tell us and will tell us whether we are going to plant broadcast 
or in rows. It is a question we have got to consider thoroughly. If I were 



142 



a plankT and planliiit;- cxiensi\cly I would be pretty cautious about getting 
late ])eas in drills; I wouldn't put all my crop in for early peas; 1 would 
risk the larger part of my crop in early peas broadcast, because at present 
there is no way of saving the plants when we have brushed and blown and 
sucked and you cannot get rid of them and cannot get at them. We have 
had men going through a field of fourteen acres blowing and brushing and 
thinking we would not leave any of the little fellows, and when we got the 
sucking machine on them we thought we had it solved. There is another 
question — that sucking machine worked all right in principle. It vou can 
do it on a small scale may be you can do it on a large scale also, but when 
you get a 6oo-acre tield — 

Mr. Hubbard: I Inw do you rccomend planting, Professor? 

I don't know, Mr. Jlubbard; that is a question, I think, for you can- 
ners to decide. I am not giving you any recommendations. I am giving 
you my opinion. I do not want any man to go on and say, "I planted on 
the recommendation of a young man that was talking through his hat." 
I am simply holding it is a jirolilcm for every one to consider. I know as a 
matter of fact Mr. Pearson is not going to broadcast his. I know that if 
this is going to strike in Indiana we would not want to be in their boots if 
it strikes them late. Those light, sandy soils, you all know, dry out very 
rapidly. If they are broadcast you have no way of getting at them. With 
a drouth combined with the insect, the insect will not take a good strong 
plant, but they will take a sickly or weak plant every time. If there is any- 
thing that reduces the plant in vitality you can rest assured that insects 
are going to attack that particular plant. .And with drouth and a plant 
weakened in vitality a man wants to be careful on these light, sandy soils, 
and use the cultivator frequently. It may not be necessary and some have 
said, "It don't pay; I get about as big result as the man who plants in 
rows ;" on the other side the man that planted in rows what he got was 
profit to him. You can rest assured if he got anything at all in compari- 
son with the man in the other locality — the man that got them bv cultiva- 
tion and brushing them, etc., he can just credit himself on his ledger with 
that much ; and that will hold good in any locality. What is going to be 
good for the northwest I don't know. I am going to be cautious about 
my statements. I am not going to advise you when I have had no experi- 
ence myself. You may broadcast two and one-half or three bushels to the 
acre if you choose. I would rather take my chances with two and one-half 
bushels in the drill, where I have a chance to work, than three broadcast 
and take my chances. It is an insurance, in other words, you can afford 
to put on that crop to insure yourself of the only possible way of saving the 
late crop, just as you would put insurance on your factory. If you did not 
burn this year is no reason why you should not insure next year. The man 
that broadcasts his late peas, if this insect does strike him as I said a mo- 
ment ago. has not a peg to stand on. In the northwest, where these insects 
breed in a field of five acres in such great numbers that the gentleman him- 

143 



self said it didn't seem possi])le that natvire could produce such number! 
as there, it seemed as if they must have rained down — there wasn't a pea 
left in that field — they simply withered and died. He is g'oing to plant his 
peas in drills. I bet he doesn't plant them broadcast, if he plants them at 
all. These were very late peas — about the 20th of July the insect struck 
them. 

Question: If they had been drilled would it have saved them? 
Would it be possible to save them if in drills, because that insect 
seemed to breed more rapidly? Here is a point: I do not believe it pos- 
sible, more rapidly than in the south or central states, but there may be 
conditions that exist — that there are greater breeding individuals in a field 
— but I don't believe the period of birth is any more rapid than in any other 
place, and I think these insects were there, probably in the early fall, but 
he didn't see them and it wasn't until he saw the decline of the peas that 
he saw them. Mr. Roe was looking for them, and many of you laid paper 
down as INIr. Chisholm and Scott suggested to see if you could find the 
green fiy. That is what Mr. Roe did, and I feel confidently certain that if 
the Wisconsin people had done the same thing they would have seen them 
four or six weeks in advance of the time they did, when there was a possi- 
bility of saving the crop. Plants become so infested that you can only see 
the flies, you could not see the plant at all. I have seen them when they 
stood, with their heads in, so closely on the stems and leaves that you could 
not see the plant. If you should go in and kill every louse the plants would 
never have overcome it. Apply the same condition to a man — cover a man 
with leeches so that you cannot see the skin — I do not care how well you 
feed him — keep him in Powers' dining room with a dozen waiters around 
him — he is not going to live. He cannot stand the drain on his system. It 
is the same with the plant on which this insect feeds. The insect has a 
lance-like beak which he inserts in the tissues of the plant itself, and you will 
almost always find what we call an oxidation of the enzymes, an oxidation 
of the coloring matter or materials within that tissue and that is efi^ected 
by the insertion of the beak. You will find a whole plant yellowing from 
the oxidation or oxidizing efl:'ect that you get from the insertion of this 
lance-like beak. 

Mr. Greenabaum spoke of spraying with peppermint. 

Yes, some insects have pretty good smellers and there have been manv 
experiments and many advantages taken of that fact, to repel insects. For 
instance, you take some of the butterflies and their sense organs are ex 
ceedingly delicate, and they detect an odor, and we have gone on the sup- 
position if they are attracted by a sweet smelling substance they would be 
repelled by an unpleasant odor. Take, for instance, the rose bug which is 
attracted by the sweet smelling substance — for instance we know the mag- 
nolia is literally covered by these bugs, and we know they are attracted by 
these sweet smells and we take the reverse and think perhaps they will be 
repelled by foul substances. We take something we might call rotten eggs, 

144 



potassium sulpliidc, wlicii in soluliun it smells like rotten eggs, and spray 
the plants thinking these inseets would be repelled and at the same time it 
would not alTt'ect the plant but it did not have the effect we expected — it 
seemed to be impervious to it. 

Mr. Goldmark : Is there any vapor that would be injurious to the life 
of the insect ? 

]Mr. Johnson : Yes, there are a number of chemicals we have tried to 
use — bisulphate of carbon, a very volatile liquid a little heavier than air. 
Mr. Scott, Mr. Roe and Mr. Chisholm rigged up a canvas and with oilcloth 
making a place perhaps larger than this room air-tight, and then they intro- 
duced this bisulphate of carljon. Ikit it would be pretty difficult to cover a 
large field. The result of the experiment was not very satisfactory. We 
know as a matter of fact that this is one of the most deadly insecticides. 

On the other hand, the hydrocyanic gas, as has been suggested, is still 
worse. The gas is lighter than air and the most deadly gas used in science, 
so that we could not for a moment trust that in the hands of the canners. 
Some of the machinery men could use it all right — but the lungs filled with 
hydrocyanic gas would kill a canncr. It is used largely in California. 
Thev are obliged to use it in orange orchards, and they use canvas covering 
the entire tree. We are applying some in some of the orchards in the east. 

The San Jose scale, in a i,ooo-acre orchard, it was discovered that about 
6,000 trees were infested, and they were all fumigated last fall, so it is being 
used bv nurserymen for the destruction of the scale before dissemination 
from the nursery, and it is also used by seed houses, especially in elevators 
where grain is stored in large quantities. I have successfully fumigated 
some of the largest mills. One mill in Canada used 75 pounds of potas- 
sium cvanide at one dose. In Baltimore I fumigated in one case 60,000 
cigars which had been attacked by the cigarette beetle. 

Question: How about the syrphus fly? 

The svrphus fly is one of these natural factors that appear almost from 
the beginning and has kept the insect down to a certain extent. In no case 
docs it seem to have increased in the same percentage with the green fly. 
While the green fly was producing at the rate of twenty to twenty-four the 
syrphus fly was reproducing only at the rate of three or four. I have found 
a number of unrecorded species feed on this green fly and the syrphus fly 
feeding in that section. \\e have got to look out for it and the canner 
must familiarize himself w^ith it so he can interpret what he sees. That is 
what we are going to do. We are going to make bugologists out of the 
canners. Already some of the more progressive canners are asking us to 
hclj) them fit up microscope outfits. You can go so far and call in and have 
the experience of others occasionally and have a lesson given you now and 
then. You have the equipment back of you to do it. It gets itself down 
to a matter of business. Some of you will within ten years, I have no doubt, 
have a microscope on your desk and use it just as much as pen and ink. 

Question : Can you brush them off — 

145 



The little fellows just born would be destroyed if you get them in the 
dirt; but with the older individual it would take an inch and a half to two 
inches earth to destroy them. Some would work out of an inch if the earth 
were dry, but if moist it would be impossible for thfem to get out of half 
an inch. 

Another question is the time. 

We found that one of those old ladies would live in her grave of an inch 
and a half of earth over forty-six hours. You can't cultivate tlie second 
day — you must wait at least until the third day. 

Question : How near can these rows be placed together and be culti- 
vated sucessfully? 

I would say thirty inches. Some advocate twenty-six, but I recommend 
thirty inches. 

The question has been asked, how these peas are dropped in these rows, 
and I think that is an important point. At Mr. Pearson's we found the use 
of a single row drill, with fertilizer attached, and that dropped the peas 
thirty or thirty-five to the foot, and as they came out they would spread 
about three inches just as they run down and we covered them up. Be- 
tween the fertilizer and the seed peas we had an agitator which covered 
the earth and we had shoes behind it which just covered the peas and fer- 
tilizer. 

Question : All done in one operation ? 

Yes, sir ; one covered them in the neighborhood of two inches. 

Question : You think that is deep enough, do you ? 

Well, of course, you might say two inches. Some of them might be 
four ; but I would say two inches. 

Question : Some one asked about worms in the ears of sweet corn. 

In the South it is known as the cotton-boll worm, and in the middle 
central south it is known as tomato worm, because it works in the tomato, 
and in the north it is known as corn ear worm because it works in the corn. 
I do not know of any remedy except in the south they plant corn around 
their cotton and the sweet corn is used as a trap. There is a suggestion, 
if the sweet corn growers could plant a crop a little earlier than the one you 
expect a little later, it might prove a preventive. They fly at night, you 
have seen them fly at night, a drab colored moth. It goes to the corn and 
deposits its egg in the silk and the worm works its way down into the ear 
and leaves a bad, objectionable ear. You might plant an early crop which 
you are planting as a trap for the worm. That is a difficult problem. You 
have got to be governed by your season. If the spring opens early you have 
got to get ready. Do not throw the whole bulk of your crop in at one time. 
This is particularly true of the late crop. There are only two broods of this 
insect and the first brood is not so great. They crawl down to the corn and 
pupate in the corn. It is the second brood that raises havoc with the corn. 

146 



CHAPTER X. 

The following' paper b}- Professor Sanderson was to have been read at 
Milwaukee at the Annual Convention. I'ebruary, 1902. Owing to blockad- 
ing snow-storms, the Professor was unable to reach the Convention city 
and the paper, therefore, was not read. It was published, however, in 
the Canner and Dried Fruit Packer, as a j)art of the Convention proceed- 
ings. The paper was as follows : 

GREEN PEA LOUSE. 

{.\ccU:rophora ("isi Kalf.) 

The green pea louse contmues to be the most important insect pest of 
interest to the canning trade. This pest has now been excessively destructive 
for three successive seasons, and though less abundant the past year, there 
seems to be every reason to believe that it is fully as liable to be injurious in 
1902 as in previous years, and it is not at all improbable that we may have 
to figiit it more or less every year. It is safe to sa\- that during the past 
three years it has occasioned a loss to those growing peas for the cannery, 
market and seed, and to the canning trade, of $5,000,000 or $6,000,000. I 
have endeavored to secure some figures as to the total amount of the pea 
pack upon which to base a rough estimate of the loss sustained, but have 
been entirely unsuccessful except for Delaware. The above estimate is 
therefore only a good guess after carefully considering the available figures. 

When the pea louse first apjx-ared so destructively in icStjO we naturally 
were led to believe that it was a new pest, h^urther studv has shown, how- 
ever, that it has been well known in luirope for about a century. Tn England 
it is known as the green dol]ihin, and is one of the worst pests of peas, clo- 
vers and vetches. Messrs. Kirby and S|)ence, English entomologists, writing 
in 181 5, give an account of the damage done peas, which is very similar to 
our own experience. "Those aphids wdiich attack ])ulse (peas) spread so 
rapidly, and take such entire y)ossession, that the crop is greatly injured, and 
sometimes destroyed bv them. This was the case in 1810, when the produce 
was not much more than the seed sown; and many farmers turned swine 
into the pea fields, not thinking them worth harvesting. The damage in 
this instance was caused solely by the aphis, and was universal throughout 

147 



the Kingdom, so that a supply for the navy could not be obtained. The. 
earlier peas are sown, the better chance they stand." It is also remarked 
that the pest is worst in dry seasons. The insect has been known in this 
country for about fifteen years, though never injurious until 1899, except in 
one or two localities to clover. In Europe the pea louse has a long list of 
food plants. We have found a variety of it upon lettuce. A recent report 
from South Africa states that it is very common there upon sweet peas and 
alfalfa, though we have not observed it to attack alfalfa in this country. 
Specimens from South Africa prove to be identical with the American and 
European species. Like many plant lice, however, this species is quite 
variable, so that three or fOur quite distinct varieties can easily be distin- 
guished when closely compared. 

I presume that the structure and habits of this pest are now well known 
to all of you, still it may not be amiss to briefly sketch the most important 
points for the benefit of those who may not have attended the last two meet- 
ings of the association. 

The pea louse passes the winter on clover or vetches. About May ist 
the winged females spread to peas, upon which they give birth young, which 
develop into wingless females. These females, as do those of subsequent 
broods, give birth to live young without intercourse with males, which oc- 
curs only in the fall, and v/ithout laying eggs, as do most insects. Repro- 
duction goes on very rapidly until the latter part of June. Winged lice 
develop as often as the food plant becomes overcrowded. About twelve 
days are required for a louse to become full grown. Prof. Johnson has 
shown that in the spring a female gives birth to no to 120 young. In the 
fall fewer young are born ; only about twenty-five by each female, in Oc- 
tober. Thus it is due to this power of extremely rapid reproduction that the 
aphids so quickly become numerous and do such serious injury. By July 
1st the lice are almost all exterminated in the latitude of Delaware, both by 
predaceous and parasitic insects and disease, and are but rarely seen during 
midsummer. In September they become common again, multiplying very 
rapidly on the few late garden peas then to be found. Late in October they 
migrate back to clover. The winged female which migrates from peas to 
clover is much smaller than the summer form, and the feelers and the back 
between the wings are blackish. About November ist a few winged male 
lice appear on the clover. They are similar in size and color to the migra- 
tory females, though slightly darker, and having black spots along the sides 
of the abdomen. By analogy with the life history of similar plant lice, such 
as the apple leaf plant louse, the appearance of a male would lead one to 
expect that the young deposited on clover by the migratory females would 
develop into true females which would lay eggs. But so far as observed 
such is not the case with the pea louse. The young born upon clover de- 
velop into viviparous females, which go on reproducing until severe weather 
sets in, and possibly without interruption in an open winter. Possibly far- 
ther north true females and eggs may occur, though careful search has not 
as yet revealed them. Early in the spring the lice commence reproducing 

148 



upon clover, and if they niul'tiply without any check from insect enemies 
or disease they spread to peas as soon as clover becomes overcrowded, or 
when approaching ripeness it loses its succulence, and they find peas a more 
desirable food. The pest is principally spread by the winged females being 
carried by the wind, they being often carried several miles, as shown by their 
being blown aboard vessels' in Chesapeake Bay from the shore. The manner 
in which they spread from clover to peas has in most cases been quite inter- 
esting, in that they migrated to only the late varieties of peas. Next to a 
badly infested field of clover was a large field of j^eas, early, medium and 
late ; only the medium and late varieties were attacked, the medium but 





Ti 


1 


h '• : 


f 


\ 


c 


1 \ 
1 '/ ' 



THK (iUKKX 1»KA I.OCSE.— (A"cf <((MI/W|.)C(/ jii'm' Kdlt.) 

A. fDurili sia;ri' wiiitrloss fi-nialo; b. wintrU'ss viviparous fcnialo and younjr: 
e. pupa: u. \viii>rt'd viviparous fenialf. (Autliors illustration.) 

slightly, and hardly an aphid was to be found on the early Alaska. A\'hence 
this nice sense of taste? 

The winged lice are from one-eighth to one-seventh of an inch long, with 
the whigs expanding about two-fifths of an inch. Most of the body is of a 
pea-green color, and light vellowish brown between the wings and on the 
head. The e\es are red. The legs, antennae or feelers, and hone\- tubes are 
yellowish, tipped with lilack. The wingless females are similar in size and 
color, but are much broader across the abdomen, and the honev tubes arc 
somewhat longer. In the young stage immediately preceding the winged 

14) 



adult the wing pads can be seen on the sides of the body, whereas the wing- 
less young are almost exactly like the adults, except that the tail is slightly 
shorter. Like all plant lice, the pea louse is a sucking insect. That is, its 
mouth parts consist of a long tube or beak, the tip of which is rested upon the 
surface of the leaf. Within this tube are four long, slender, needle-like 
bristles, which are worked rapidly up and down, lacerating the tissue of the 
leaf and thus setting up a flow of its juices, which are then sucked up through 
the tubelike beak. With large numbers of the lice sucking out its juices 
the plant soon withers and dies. Of course, with such a mouth structure it 
is of no use to apply poisons to the surface of the foliage for this pest, and 
if we are to kill it by spraying, some spray must be used which will act as an 
irritant or clog the breathing pores. This is accomplished by using kero- 
sene and water or whale oil soap. 

Before passing to a consideration of the remedies for this pest, let me 
call your attention to some of the most important agencies which hold it in 
check, namely, insect enemies, disease and weather conditions. 

The pea' louse seems to have but few internal parasitic insects preying 
upon it, though many plant lice are almost entirely held in check by these 
parasitic flies. In 1899 but few parasitized lice were found and those in the 
fall. In 1900 they were more numerous, probably about 5 per cent of the 
lice being killed by them in Delaware, but being of relatively little value in 
holdmg the pest in check. These parasitic flies are small insects, even smal- 
ler than the lice. They deposit an egg upon a plant house, the maggot hatch- 
ing from which feeds upon the juices and tissues of the louse, ultimately 
killing it. The dead louse swells up, becomes brown and dry, having a very 
characteristic bladder-like appearance. When the maggot is full grown it 
transforms to a pupa, which soon turns to the adult fly. In emerging from 
the dead plant louse the fly cuts a smooth, round hole, the piece cut out often 
remaining attached, like a lid. 

Syrphus Flies. — Among the most beneficial insects predaceovis upon the 
louse are the maggots of the syrphus-flies. Three species very commonly 
feed upon it, the American syrphus-fly (Syrphiis Aincricana IVcid) being 
the most numerous. These syrphus flies deposit a single oval, white egg in a 
colony of plant lice. From this hatches a small maggot, which becomes 
about one-half to five-eighths of an inch long when full grown, of a green 
or brownish color, mottled with reddish, and with several pointed tubercles 
along the back and sides. These maggots have no legs nor distinct head, 
the head segment looking much like the rest of the body. But in it are a 
pair of small, stout hooks. When a louse is grasped by these it is held aloft, 
the maggot waving it to and fro in the air, and the juices of its body are 
quickly sucked out. In this manner I have observed one of these maggots 
to eat twenty-five lice in as many minutes. Late in the season when these 
maggots become numerous the refuse from the vines will be almost green 
with them, and they can be scooped up by the basketful. Two other species 
Df syrphus-flies {SpliacropUoria cylindrica Say.) with similar habits were 
common. One of these (allograpta obliqna) was badly killed off by internal 



150 



parasites. One of tliese is a small \vasi)-like tly (Bassiis lac'otoriits Fab.) 
and the other similar to the parasitic tly feeding on the pea louse. So all 
parasitic insects are not beneficial ; some, like these, preyinq- upon insects 
themselves beneficial to man's interests. 

Lady-bird Beetles. — Almost all of the common lady-bird beetles feed 
upon the pea louse, thou^ih thev do not become abundant until earlv in June. 
These little orang-e, or reddish, black-spotted beetles, lay their small orange- 
yellow eg-gs in small clusters on the pea's foliage. From them hatch active 
little six-legged larva;, which have been fancied to resemble miniature alli- 




A.MKHRAN SYHIMICS FI.Y. 

A. larva or nia^r^rot caliiitr a i)ca li)use; u. mipariiim. or pupa ■■asc. fniui wliii-li 
adnli lly lias (■iiii-rtrcd. cud broUcu opcii; r. adult tly. (I'roiii i)li<)t<is by .Xuiluir.) 

gators. \\ hen full grt)wn these larva? are about one-half an inch long, blue 
or black, spotted with orange, and with numerous small warts or tubercles 
bearing black spiny hairs, scattered over the body. Each larva then attaches 
itself to the leaf by its tail, so to speak, and sheds its skin, transforming into 
pupa, a dozen of which are ofien found on a vine. The pupa hangs pendant 
from the leaf for a week or so. when the adult beetle emerges from it. 
Though both the larv;e and adults of these beetles eat large numbers of pea 

151 



lice, they do not become sufficiently numerous until too late to prevent the 
worst injury. 

The Lace-Wingcd Fly. — This is one of the most interesting enemies of 
the pea louse. Its larvre are quite common in the pea fields and consume 
many a louse. The adult f\y is a bright pea-green color, with the veins of 
the wings forming a fine lace-like network, and with shining golden eyes, 
on account of v/hich it is often called "Golden Eyes." Its eggs are laid 
singly, sometimes several on a leaf, and each is placed on the tip of a stalk 
of silk. Were it not for this ingenious device, when a young larva hatched 
it would undoubtedly devour all the remaining eggs. As it is, older larvae 
often eat their younger brothers and sisters. These larvse are smaller and 
much more active than those of the lady-bird beetles. Projecting from the 
front of the head are the two long sickle-shaped jaws, which are hollow. 
With the tips of these a louse is firmly grasped and its juices sucked into the 
mouth through the hollow mandibles. When full grown the larva spins 
around it a small globular, glistening, white silken cocoon, and within it 
transforms to the pupa, which in due time transforms to the adult fly. I 
found that one of these flies laid about forty-five eggs in a day in confine- 
ment, they hatching in about a week. 

Alany other insects feed upon the pea louse, but these have been the most 
important observed in Delaware. Though they do a great deal to lessen 
the numbers of the lice, they do not multiply with sufficient rapidity to enable 
them to materially check the lice until the worst injury has been done, so 
that in years when the louse is injurious no dependence can be placed upon 
them, though most years they undoubtedly are one of the most important 
factors in holding it in check. 

Disease. — The most important enemy of the lice is a fungous disease — 
entoiiioplnthora aphidis. Lice killed by this disease are shriveled and cov- 
ered with a sort of brown mold. In 1900 dead lice killed by this disease were 
found on clover early in the season, but not in any quantity until June 11. 
After that, so rapidly did the disease destroy them that a week later but very 
few lice were found, and almost all were diseased. Diseased lice were com- 
mon on peas in the fall of 1899, but were much more numerous on peas and 
clover during the fall of 1900. In 1890, when clover was injured by the 
lice in Delaware in May, they were destroyed by this fungus by May 12. 
This disease also holds the louse in check in South Africa. As yet no means 
is known whereby this disease may be propagated. Could some method 
of growing it be found, it might be the means by which the pea louse could 
be effectually controlled. 

Causes of the Outbreak. — Primarily, I believe the cause of the unusual 
outbreak of this pest in 1899 '^"^l its injury during the past two seasons to 
be due to weather conditions. To the peculiar weather conditions were 
doubtless due the disappearance of two of the factors which go to hold the 
louse in check. The severe blizzard of February, 1899, may very probably 
have killed off many of the internal parasites of the louse, and thus left the 
latter free to increase abnormally. This seems the more probable as but 

152 



few internal parasites were found in 1899, and their being more common 
in 1900. But the chief factor in nature's control of this pest seems to be 
the fungous disease. The growth of this disease requires wet weather, and 
is prevented by drought. April. May and June, 1899, in Delaware, Mary- 
land and New Jersey, were together the driest for the past ten years and, 
with local exceptions, this was true throughout the Atlantic coast, Ohio val- 
lev and Lake region. Not only this, but there had been a marked deficiency 
in rainfall during the two previous years (1897-98) in the spring and for 



f 



a. 





LACK WIMiKD Kl.V.— (f 7u(/>'i/'(( oillldlll S(tll.) 

A. ailiili ll.v: H. iiaril.v srrowii larvae: c. inipa. i I'loiii i>li'>i«>s I'.v a\ii lior.^ 

the whole year, even the spring of 1896 being exceptionally dry in Delaware. 
In 1899 the fungus did not destroy any considerable number of the lice until 
about' June 18, and their destruction seems to have been most largely due 
that year to the predaceous insects. In 1900 the disease appeared much 
earlier, destroyed large numbers of the lice and their disappearance by the 
1 8th of Tune was most largely due t(i it. In 1890 the lice were destroyed 



153 



by this disease at Newark, Del., on clover by May 12. The rainfall of May, 
1890, was above the normal, at Newark, and the preceding" winter was a mild 
one, corroborating the view that a wet spring is favorable to the development 
of the fnngus, which destroys the aphids on the clover and prevents their 
spreading to the peas. As before noted, Kirby and Spence many years ago 
stated that the louse was much worse in hjigland in dry seasons. The past 
season we had an unusually wet April in Maryland, Delaware and New Jer- 
sey, a more than normal rainfall in May and about the average in June. 
Throughout the jjea-growing states there was a normal or excessive rainfall 
during these months. As a result in Maryland, Delaware and New Jersey 
there was little or no damage to early peas by the louse, and by no means 
as much to late sorts as in the previous two years, and I am informed that 
in the north but little damage was done. 



Ili»W TO C(JMi:.\T Till-: I'KST. 

Prcvcntii'c M cons. — Mamii^ciiiciit of Clover. — Inasmuch as the lice spread 
from clover to the peas, it will be advisalile to i)lant as little clover next the 
jicas as possible. In the spring the lice should be carefully watched on the 
clover. Should they become overabundant, the management of the clover 
will depend on several factors. It has l)cen planted as a cover crop to be 
turned under, it will probably be best to turn it under deeply at once, even 
though it has not made the desired growth. If planted for hay, its treat- 
ment will depend upon whether it or the peas are of most value. 

Planting in Rozvs. — Peas sown broadcast or i)lanted in 8-inch drills have 
universally been much more seriously injured by lice than those planted in 
rows twenty to thirty inches apart and cultivated. Furthermore, peas not 
sown in rows afford no op])ortunity for brushing, cultivating or s])raying. 
It is therefore absolutely neeessary that peas be jilanted in rows as long as 
there is any danger of the appearance of the louse. 

Re)nedial Measures. — BrusJiiiig Pollozced by Cultivator. — Prof. Johnson 
found in 1900 that when peas were planted in rows the lice could be readily 
knocked from the vines by means of brushing with a pine branch, and that 
by thus knocking the lice off between the rows and cultivating at once the 
lice would be destroyed by their dying from suffocation under the earth or by 
the heat of the soil. Prof. Johnson stated : "Where the lice are brushed off 
on the ground in tlie hot sun, with the thermometer varying from 94 to 96 
degrees I'ahr., they are actually roasted to death in a few minutes. The 
temperature of the ground was from 113 to 119 degrees Fahr. The culti- 
vation should not be repeated until the thinl day, as it requires usually some- 
thing over forty-eight liours for the destruction of the adult insects covered 
by earth" (i. e., if the soil is not hot enough to kill them at once). "Peas 
that will not admit of fref|uent cultivation should be brushed at midday." 
P)y the use of this method several i^arties in Maryland were in 1900 able to 
save considerable areas of peas. This method was used with some success 
in Delaware, but it was fre(|uently fouml that when the soil was 

15.S 



moist It would lorni small clods after cultivation and that the lice 
would then mcr<?l\- crawl out from under tliem back to the vines. 

Brushing into Pans. — To meet this difficulty Prof. Johnson devised an 
arrang^ement into which the lice might be brushed and thus caught. This is 
modeled after the "hopper dozers" used in the west for catching grasshop- 
pers, and consists of a long, shallow pan the width of the rows and live or 
six inches deep, with one or two cross partitions. In the bottom of this 



\i 



v^ 



^ 



.1^:: 






u 




\ * 



E(t(iS DK LACK WINC.KI) FI.V AND VV.X I.ICK KIIJ.Kl) ItV l'l-.N(;ors DISKASE. 

{KntiiniiiiilKiiii (tiihiilin.) (I'roTii pliolo l>.v aiil linr.) 

pan is placed a little water, which is covered with kerosene. This pan is 
drawn between two rows, while a boy on each side brushes the lice into it, 
where they are soon killed upon coming in contact with the kerosene. The 
pan should be frequently cleaned out, so that it will not become filled and 
thus prevent those falling in from coming in contact with the kerosene. 
These ])ans r.ia\- be easily and cheaply made and operated at small cost. The 

157 



hopper dozers have l)eeii used for many years in Minnesota and the west, 
over thousruids of aeres, with the best (jf sneeess, and we would commend 
this method of fi,c^htin«^ the pea louse in i)reference to the "Ijrush and culti- 
vator" method, if sjjraying is for any reason un])racticable or undesirable. 

Sf'rayini^. — In 1900 I experimented at Mr. Cannon's in a small way in 
sprayint^ with a kerosene and water mixture. We found that 15 per cent, 
kerowattr was ineffectual against the louse on a hot day, as it evaporated so 
rapidly that no injury was done the lice; 25 per cent., however, killed the 
lice — all It hit and did no injury to the vines as far as we tried it — (jn about 
one-fourth an acre. Almost all of the lice were thus killed by thoroughly 
spraying tl'o \ ines by means of an attachment to a kerowater pump, by 
means of which four rows were covered at once, one spray nozzle to each 
row. lUu knowing that at this strength the kerosene was very liable to 
injure ihc \ines. when used on a large scale, no further tests were then made. 
Our work convinced us that with four nozzles to a row, so that the vines 
could he thoroughly sprayed, and with the pump geared to the wheel of the 
cart, the pea louse could be successfully coml)ated by sjiraying, even on a 
large scale. Prof. Johnson also tried spraying with whale oil soap, but with- 
out much success. We believe that this was due to an insufficient number of 
nozzles, as he used but one nozzle to the row. so that the spray came from 
above and the sides 01 tiie piant and under surfaces of the leaves were doubt- 
less not covered. 

We were led to give attention to the possibility of jjrohtabl}' sjjraying 
for this pest on account of the fact that some growers had not been success- 
ful with the "brush and cultivator" method, it failing to destroy a very large 
percentage of the lice brushed off on cool days or on stiff' soil forming lumps 
when cultivated. Furth.crmore. it is evident that in brushing, using either 
the cu!ti\ator or the pan drawn between the rows, the large numbers of 
the adult lice might be destroyed, inasmuch as the young lice in the buds are 
not disturbed, it would be im]:)ossible to check the development of the first 
brood of the pest by brushing, as might be done by a spray which would reach 
and destroy the young lice resting securely between the terminal leaves. We 
therefore planned to construct an attachment to a barrel sprayer which would 
cover se\eral rciws with several nozzles to each row. and had submitted our 
plans to several pump companies, when we learned that Messrs. P)rakely 
of IVirdentown. X. J., had constructed a satisfactory sprayer, and had in 
1900 successfully combated the pea louse with it, using some 140 barrels of 
whale oil soaji. I'jion corresponding with Messrs. T.rakeley we learned that 
they considered the sprayer entirely satisfactory ; after having sprayed a 
large acreage and saved their crop by means of spraying last year, that they 
had duplicated their order for 140 barrels of whale oil soap, and intended 
to spray their whole crop of 500 acres this year. Feeling satisfied that these 
gentlemen must have solved the problem of spraying the pea louse, we 
dropp'^1 the construction of a pump and awaited a public exhibition of their 
luachinc with interest. This took place on May 13, when Messrs. Rrakcley 
kindly invited a number of persons interested to inspect the working of the 

159 



sprayer in the field. Among the party were Dr. J. B. Smith, New Jersey 
State Entomologist. 

At a distance the sprayer looks something like a large grain drill. It 
consists of a large tank, containing a simple pump, with air chamber above 
tank, which is attached by gear to one of the wheels of the two- wheeled 
truck. Beneath the tank are pipes leading to nozzles, and the guides and 
lifters for holding the vines erect while they are being sprayed. The sprayer 
covers three rows at once, the peas having been planted in this way, but 
the inventors think that planting two rows at once and having a sprayer cov- 
ering two rows would be preferable. As the sprayer passes along the vines 
are picked up by a wooden V-shaped piece, similar to a plowshare, and pass 
between parallel iron bars which hold them upright. These bars are mov- 
able, so that they do not tear the vines. Above each row is a cluster of 
three nozzles — Bordeaux nozzles are used — one directed forward, one back- 
ward and one straight down. On each side of each row are two nozzles, one 
directed forward and one backward, and just above the ground on each side 
is a nozzle directed upward, so as to give a thorough under spray. On either 
side beneath each row is a wide board which catches all the lice knocked off 
by the machine and upon which they are sprayed. The whole under part of 
the sprayer — nozzles, guides, etc. — can be thrown up about a foot by means 
of a lever, permitting the turning of the sprayer, and can also be adjusted 
for different height vines. The machine is simple and practical. 

Messrs. Brakeley were just finishing a twenty-four-acre pea field, upon 
which six sprayers had been working half a day, when we arrived. The 
vines were about fifteen inches high, being Champion, Jr., a medium late, 
sweet wrinkled pea. The lice were not very numerous, though almost every 
tip contained a small family of fast-maturing young. The vines were very 
thoroughly covered by the spray, and as nearly as we could approximate it, 
from 80 to 90 per cent, of the lice were killed ; had they been thick, at least 
95 per cent, or more must have been destroyed. On May 20 Mr. Brakeley 
wrote me that he could find but very few lice in this field, which was then 
about ready to cut. Later he wrote that where the vines were sprayed 
promptly about May 13 to 15 a good crop was secured and but little injury 
was done, but that where spraying was delayed till later the crop was con- 
siderably damaged by the louse. Whale oil soap was sprayed at the rate of 
one pound to six gallons of water. It had been used more dilute, but it was 
found a larger cjuantity was then necessary, and it was therefore better to 
use it stronger to avoid handling of material. When the vines are small 
about 160 gallons, and when nearly full grown 300 gallons are used per acre, 
which at 3 cents per pound of soap would mean $1.50 an acre for materials. 
The soap was readily mixed with cold water, one barrel of soap being mixed 
to form three barrels, and this then dipped into tanks in which it was diluted 
and carried to the sprayers. The water for the tanks was pumped up from 
a small brook h\ means of a traction engine. One tank carried the soap solu- 
tion for each sprayer. With six sprayers, six tanks, engine and three extra 

16O 



men, fifty acres a day were sprayed at a cost of $42.50 for labor and $75 for 
materials, or a total cost of $244 — say, $2.50 per acre. 

This may seem a gootl i)nce to pay for combating' the pea louse, but when 
one spra\ing. will insure a tirst-class crop of medium and late peas, while 
otherwise they would be of inferior grade, those who are growing a first- 
class article can well afford the expense, and were the lice thick enough to 
threaten the life of the crop, two sprayings wotild certainly be profitable. 
Mr. Brakeley sprayed his whole crop of 510 acres, all owned by himself, and 
though tlie lice did not seem to be thick enough to do any serious dam- 
age when examined ]\la\- 13, yet it seemed to ]\Ir. IJrakeley and my- 
self tiiat s]. raying would be profitable, which, as before stated, proved 
to be true. Flic sprayer was invented by Messrs. Brakely, sons of A. 
Brakeley. of A. Brakely & Sons, and is covered by patents (668,951, 
Feb. 26. 1901, and 669,818, March 12, 1901). They were unable 
to give us an exact estimate of the cost, but it was thought bv those 
present that thev could be built to order for $150 to $200, and possibly less 
^f manufactured injiumbcrs. Of course a small grower could hardly afiford 
to own and operate such an outfit, but where peas are grown for the cannery 
on contract, the canncr might own and operate the machine, or some one 
owning a traction engine or doing similar work might find it profitable. 
Messrs. lirakeley's sprayer was granted patents upon the combination of the 
device for lifting the vines and nozzles for spraying them. Various arrange- 
ments of nozzles for spraying crops in rows have previously been patented 
and put upon the market by spray pump makers. Early in the season, while 
the vines are still uiiright, we believe that any machine which will sprav two 
or three rows with four or five nozzles to the row, will be found satisfactory 
— and early in the season, before the lice have become numerous, is the 
time to spray with profit. But as the vines fall over and run a device for 
lifting them is absolutely essential, and Brakeley 's spraver is of value. 

If the pea louse is to be with us every year — as it now looks — and we 
must fight it by spraving. it will be found desirable to raise low-growing 
sorts and to plant in perfectlv regular rows. 

Should the weather conditions be unfavorable for its development, the 
next season may see a practical disappearance of the pea louse, but, on the 
other hand, it may be as bad as ever, and should it not occur in 1902. or in 
1903. it may appear any spring as suddenly as in 1899. As it should be 
foug-ht early in the season to prevent injury. I believe that spraving- will be 
found profitable, and that the possession of a first-class spraving outfit, with 
a supply of soap, all readv for use. and then its prompt use. will solve the 
problem of growinq- peas in spite of the pea louse. T do not know that it is 
now in order, but I believe, gentlemen, that it is proper, and I can support 
the good deacon in saying. "Let us ('s)prav." 



161 



CHAPTER XL 

OUTLINE OF PROCESS OF PACKING PEAS BY THE 
MOST APPROVED METHODS. 



BY 
CLAKKXCK H. IM.l'MMKU 



Formerly it was customary to plant peas, for cannin<j: factories, in rows 
in the field, and make several pickings over the same field as the crop ma- 
tured, but at present the method ni planting; and packing most used is as 
follows : The peas are sown in drills, same as in the case of small grains, 
and when the most advanced parts are fully matured, but before the ripening 
or hardening process sets in, the vines are pulled and all pods removed, put 
into bags and carted to the factory to be podded by the "Pod HnUin;^ Ma- 
chine." or where "J'iiiins; MacJiiiics" are used, the entire vines, witli adhering 
parts, are carted to the factory on racks similar to hay racks. 




THK SKIl)r> VV.\ MOWIMi ATTACHMK.NT 



The hulling operation is the first that is performed. This is accomplished 
by the use of machines which beat tlie peas out of the pods — the Pod Hiilliui^ 
Machine or the [';';//';/ <^ Machine. These are very similar in cc^nstruction. the 
former treating the pods after they are removed from the vine, and the 
latter treating the entire vine with pods attached. I'oth machines discharge 
the hulled peas separate from the pods or vines. 

The peas are next treated in a machine known as a Cleaner, in which bv 

163 



means of an air blast or through suction in combination with large and small 
screens, all fine dirt, pieces of pods, and other foreign substances are as far 
as possible removed. The peas then go to the Grader, which separates 
them according to size, each size being discharged into the separating re- 
ceptacle, from five to seven sizes being the usual gradation. To these various 
grades are given the trade names of Marrowfat, Early June, Fancy Sifted, 
Extra Fancy Sifted, Petit Pois, etc. 

The next operation is the washing and Jiand picking (the peas may be 
washed before or after picking, or even before the grading, if so desired). 
The washing is done by means of revolving cylinders of perforated metal 
or wire mesh provided with perforated pipe, which throws a spray of cold 
water upon the peas as they travel forward. For the hand picking, devices 
known as Pickling Tables are employed, the peas being automatically dis- 
tributed upon a belt or apron which slowly passes under the hand of the 
operator, who removes all discolored peas or foreign matter. The peas 
are now ready to be blanched, the prime object of which is to thoroughly 
remove all the juices which may remain in the peas after the former opera- 
tions, and also to moderately parboil the peas. The Blanching machine best 
adapted for this purpose is described as follows : A series of three tanks 
through wdiich the peas are carried by means of spiral flanged conveyors, 
each mounted in and riveted to a perforated drum or cylinder. The whole 
comprising a series of revolving conveyors which pass the peas along- through 
each successive tank of water. The spiral flange, which moves the peas 
along, is wide enough to project above the surface of the water so that the 
peas cannot lag behind. The water is introduced into the last tank first in 
a small stream, overflows from it into the intermediary tank or tanks, and 
then into the first tank, whence it overflows. In the first tank the gum and 
juices adhering to the peas are nearly all removed by the first bath; in the 
second succeeding tank the contamination of the water is reduced, and in 
the last tank the water is scarcely contaminated at all. This method of thor- 
oughly washing the peas is superior to the old methods by which the peas 
were JDlanched in the same water all through the time they remained in the 
bath. In this machine the peas are constantly moving and rolling. All re- 
ceive the same heat and the attrition of the peas one against the other cleans 
them very thoroughly. 

After blanching, the peas, as they are discharged into buckets from the 
blancher, are usually again sprayed with cold water and then delivered to 
the Filling Machine, which measures and places in each can the desired 
amount of peas and hot liquor. The most approved machines of this type 
take the cans in single line and discharge them in single line without the 
use of trays or other separate receptacles for holding the cans while being 
filled. From the Filler the cans pass through the operations of wiping, 
fluxing of the caps after same are placed on the cans, and the sealing or 
soldering of the caps onto the cans. The wipinof. fluxing and capping opera- 
tions are preferably accomplished by means of combined JViping and Cap- 
ping machines, which take the cans in single line on same general principle 

164 



as the Filling Machine, and which work in antomatiic connection with the 
latter. It is extremely desirable that each operation should be expeditiously 
performed that the peas may not deteriorate through delay in handling. 
The special machines now on the market designed to operate in continuous 
automatic line make this important consideration possible of accomplish- 
ment. The final treatment of the peas, now hermetically sealed, is the com- 
plete sterilization of can and c(Mitents. and is accomplished by means of 
Pressure Retorts, or the use of other sterilizing:; apparatus adai)te<l to main- 
tain a temperature greater than boiling point of water, such as the automatic 
calcium processing system. After sterilizing it is important that the cans be 
quickly cooled, as continued high temperature tends to cause cloudiness of 
the liquor in the can. The whole aim of the entire process must be to pro- 
duce an article which, when opened, will present bright, clean liquor, whole 
and evenly graded peas, uniform in color, tender, attractive in appearance, 
and palatable. There is probably no vegetable packed in cans which will so 
unmistakably show the degree of care taken in its preparation than the fin- 
ished can of peas. 



t«5 



Modern Canning Machinery mentioned in Mr. Plummer's article on 
the Process of Packing- Peas. 




THE PEA HULLER 



166 



Modern Canningr Machinery, mentioned in Mr. Plummer's article 
on the Process of Packintj- Peas. 




"GLIPPEK" pea CLEAXElt. 



167 



Modern Canning- Machinery mentioned in Mr. Plummer's article on 
the Process of Packinsf Peas. 




■ CLIPPER PICKING AND SORTING TABLE. 



This illustration shows the foot machine, a series of these tables 
side by side can be operated by power from one shaft. 



168 



Modern Canning Machinery, mentioned in Mr. Plummer's article 
on the Process of Packing- Peas. 




TIIK MOMTOI! I»KA SKPAHATOU OTl OTIADF.TI. 



169 



Modern Canning- Machinery, mentioned in Mr. Plummer's article 
on the Process of Packings Peas. 




THE PIjUMMEB pea FILLING MACHINE 
(AUTOMATIC BBINER ATTACHED) 



The machines and apparatus for wiping, flux- 
ing, soldering- caps, and sterilizing are the same 
as employed in packing corn, etc. See Prof. 
Prescott's article on Process of Packing- Corn. 



172 



THE SPRAGUE CANNING 
MACHINERY COMPANY 



MANUFACTURERS OF 



AUTOMATIC CANNING 
MACHINERY 



and Dealers in Canning Factory Apparatus 
and Supplies 



FACTORY '^ SALES OFFICE- 

O 
O 



HOOPESTON.ILL. o "^ ^ River street 

o CHICAGO, ILL. 



DANIEL G. TRENCH & CO., CHICAGO 

GENERAL AGENTS 



-BRANCH SALES OFFICES- 



PHILADELPHIA, PA., - GEO. E. LOCKWOOD, agent 
PORTLAND, ME., - - HENRY R. STICKNEY, agent 
UTICA, N. Y., - - - S. F. SHERMAN, agent 

SAN FRANCISCO, CAL., BERCER, CARTER &C0., agents 



Catalogues and List of Publications relating to the CANNING 
INDUSTRY furnished on application. 



ONE COPY RECEIVED 
NOV 26 1902 



jIlimnininniiiiiHimHiHiiHuuKUitHHiiiimiiiiHiuui 

LIBRARY OF CONGRESS 



illliiil 11 llllllllll 

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